HISTORY

HISTORY

A good place to start examining the history of speech sound analysis goes back a little more than one hundred years to Alexander Melville Bell who developed a visual representation of the spoken word. This visual display of the spoken word conveyed much more information about the pronunciation of that word than the dictionary spelling could ever suggest. His depiction of speech sounds demonstrated the subtle differences with which different people pronounced the same words. This system of speech sound analysis developed by Bell is the phonetic alphabet which he called "visible speech".5 His method of encoding the great variety of speech sounds was by handwritten symbols and was language independent. This code produced a visual representation of speech which could convey to the eye the subtle differences in which words were spoken. This system was used by both Bell and his son, Alexander Graham Bell, in helping deaf people learn to speak.6

It was in the early 1940's that a new method of speech sound analysis was developed. Potter, Kopp & Green, working for Bell Laboratories in Murray Hill, New Jersey, began work on a project to develop a visual representation of speech using a sound spectrograph. This machine, an automatic sound wave analyzer, produced a visual record of speech portraying three parameters; frequency, intensity and time. This research was intensified during World War II when acoustic scientists suggested that enemy radio voices could be identified by the spectrograms produced by the sound spectrograph. The war ended before the technique could be perfected.

In 1947, Potter, Kopp and Green published their work in a book, the title of which was borrowed from Alexander Melville Bell, Visible Speech. Their work is a comprehensive study of speech spectrograms designed to linguistically interpret visible speech sound patterns. This work was similar to that of Bell's in that speech sounds were encoded into a visual form. The difference is, instead of a pen, Potter, Kopp and Green used a sound spectrograph to produce the visual patterns.

Research in the area of speaker identification slowed dramatically with the end of

World War II. It was not until the late 1950's and early 1960's that the research began again. It was at this time the New York City Police Department was receiving a large number of telephone bomb threats to the airlines.7 At that time Bell Laboratories was asked by law enforcement officers to provide assistance in the apprehension of the individuals making the telephone calls. The task of developing a reliable method of identification of a speaker's voice was given to Lawrence G. Kersta, a physicist at Bell Laboratories who had worked on the early experiments using the sound spectrograph. In two years Kersta had developed a method of identification in which he reported results yielding a correct identification 99.65% of all attempts.8

It was in 1966 that the Michigan State Police began the practical application of the voice identification method in attempting to solve criminal cases. A Voice Identification unit was established and the unit personnel received training from Kersta and other speech scientists. During the first few years the voice identification method was used only as an investigative aid.

The first court of published opinion to rule on the admissibility of voice identification analysis was in the case of United States v. Wright, 17 USCMA 183, 37 CMR 447 (1967). This was a court martial proceeding in which the appellate court affirmed the admission of spectrographic voice identification evidence by the board of review. The lengthy dissent by Judge Ferguson based on the requirements for acceptance of scientific evidence spelled out in Frye v. United States, 293 Fed. 1013 (CA DC Cir) (1923), was the beginning of a controversy which continues today.

The first non-military case to review the admissibility of voice identification evidence was the New Jersey Supreme Court in State v. Cary.9 In this case the court stated that "the physical properties of a person's voice are identifying characteristics".10 The court also noted that trial courts in the states of New York and California have admitted voice identification evidence but that these admissions have not been subject of appellate review.11 The court declined to rule on the admissibility issue and remanded the case to determine if the equipment and technique were sufficiently accurate to provide results admissible as evidence. The Superior Court of New Jersey, on appeal from a denial of admission after remand, held that the majority of evidence "indicates, not that the technique is not accurate and reliable, but rather that it is just too early to tell and at this time lacks the required scientific acceptance".12 The New Jersey Supreme Court reviewed this decision and once again remanded for additional fact finding "in light of the far-reaching implications of admission of voiceprint evidence".13 The State of New Jersey was unable "to furnish any new and significant evidence" by the third time the New Jersey Supreme Court reviewed this issue and as such affirmed the trial court's opinion excluding voice identification evidence.14

California came to a similar holding when the issue first reached the appellate level in People v. King.15 The State brought in Lawrence Kersta as the voice identification expert to testify as to the reliability of the technique. The defense brought in seven speech scientists and engineers to rebut Kersta's claims. The court held that "Kersta's claims for the accuracy of the `voiceprint' process are founded on theories and conclusions which are not yet substantiated by accepted methods of scientific verification".16 The court cited the Frye test as the proper standard for admissibility.17 The court also left the door open for future admission by saying when voice identification evidence has achieved the necessary degree of acceptance they will welcome its use.18

In State ex rel. Trimble v. Heldman 19, the Supreme Court of Minnesota held that "spectrograms ought to be admissible at least for the purpose of corroborating opinions as to identification by means of ear alone".20 The court was impressed by the testimony of Dr. Oscar Tosi who had previously testified against the use of spectrographic voice identification evidence in courtrooms, but after extensive research and experimentation now described the technique as "extremely reliable".21 The court made reference to the Frye test and to the scientific community's acceptance of Dr. Tosi's study, but did not specifically apply the Frye test as the standard for the admissibility of the voice identification evidence.22 In discussing the issue of admissibility the court held that it was the job of the factfinder to weight the credibility of the evidence.

"The opinion of an expert is admissible, if at all, for the purpose of aiding the jury or the factfinder in a field where he has no particular knowledge or training. The weight and credibility to be given to the opinion of an expert lies with the factfinder. It is no different in this field than in any other".23

In 1972 the third and fourth District Courts of Florida, in separate opinions, held admissible the use of spectrographic voice identification evidence.24 The court in Worley held that the voice identification evidence was admissible to corroborate the defendant's identification by other means. The court stated that the technique had attained the necessary level of scientific reliability required for admission, but since it was only offered as corroborative evidence, the court refused to comment as to whether such evidence alone would be sufficient to sustain the identification and conviction.25

The third District Court of Appeals of Florida did not limit the admission of spectrograph evidence to corroborative status. In the Alea opinion the court does not mention the Frye test as the standard to be used for admission, but rather states that "such testimony is admissible to establish the identity of a suspect as direct and positive proof, although its probative value is a question for the jury".26

In the case of State v. Andretta 27, the New Jersey Supreme Court stated that there was much more support for the admission of spectrographic voice identification evidence than at the time they decided Cary, but refused to address the issue further since the only issue before them was whether the defendant should be compelled to speak for a spectrographic voice analysis.28

In California the Court of Appeal affirmed the trial court's admission of voice identification evidence in the case of Hodo v. Superior Court.29 Here the court found the requirements of Frye had been met in that there was now general acceptance of spectrographic voice identification by recognized experts in the field. The court cited Dr. Tosi's testimony that "those who really are familiar with spectrography, they are accepting the technique".30 Tosi also pointed out that the general population of speech scientists are not familiar with this technique and thus can not form an opinion on it.31

The court in United States v. Samples 32 held that the Frye test of general acceptance precludes too much relevant evidence for purposes of the fact determining process at a revocation of probation hearing and the court allowed the use of spectrographic voice identification evidence to corroborate other identification evidence.33

In 1974 the case of United States v. Addison 34 rejected the admission of voice identification evidence saying that such evidence "is not now sufficiently accepted" and as such the requirements of the Frye test were not met.35 At the trial the court heard from two experts endorsing the technique, Dr. Tosi and a recent convert to the reliability of the technique, Dr. Ladefoged. Only one expert, Dr. Stuart, testified that he was still skeptical of the technique and thought that most of the scientific community was also.36 Although the admission of spectrographic voice identification evidence was held to be error by the trial court, the appellate court refused to overturn the conviction due to overwhelming amount of other evidence supporting the conviction.37

Attempted disguise or mimic were the grounds the California Court of Appeal used to reverse a conviction based in part on spectrographic voice identification in the case of People v. Law.38 The court found that "with respect to disguised and mimicked voices in particular, the prosecution did not carry out its burden of proof to demonstrate that the scientific principles pertaining to spectrographic identification were beyond the experimental and into the demonstrable stage or that the procedure was sufficiently established to have gained general acceptance in the particular field in which it belongs".39 The main concern of the court was that no experimentation had been completed studying the effects of attempts to disguise or mimic on the accuracy of the identification process. Without mentioning the Frye test this court used the standards set in Frye as the test of admissibility although the court seemed to be limiting the scope of the opinion to cases involving disguise or mimic.

In United States v. Franks 40, the Sixth Circuit Court of Appeals held spectrographic voice identification evidence to be admissible. The court said it was "mindful of a considerable area of discretion on the part of the trial judge in admitting or refusing to admit evidence based on scientific processes".41 Quoting from United States v. Stifel 42, the court pointed out that "neither newness nor lack of absolute certainty in a test suffices to render it inadmissible in court. Every useful new development must have its first day in court. And court records are full of the conflicting opinions of doctors, engineers and accountants...".43 The court in Franks found that extensive review was given to the qualifications of the experts and opportunity to cross-examine the experts to determine the proper weight to be given such evidence.

The Massachusetts Supreme Court, in Commonwealth v. Lykus 44, allowed the admission of spectrographic voice identification evidence saying that the opinions of a qualified expert should be received and the considerations similar to those expressed in Frye should be for the fact finder as to the weight and value of the opinions. The court gave greater weight to those experts who had had direct and empirical experience in the field as opposed to those who had only performed a theoretical review of that work.45 The court also stated that "neither infallibility nor unanimous acceptance of the principle need be proved to justify its admission into evidence".46 The Massachusetts Supreme Court again, that same year, found no error in the use of spectrographic voice identification evidence in the case of Commonwealth v. Vitello.47

The Fourth Circuit Court of Appeals, in the case of United States v. Baller 48, allowed the admission of spectrographic voice identification evidence saying unless it is prejudicial or misleading to the jury, it is better to admit relevant scientific evidence in the same manner as other expert testimony and allow its weight to be attacked by cross-examination and refutation.49 The court listed six reasons supporting admission; the expert was a qualified practitioner, evidence in voir dire demonstrated probative value, competent witnesses were available to expose limitations, the defense demonstrated competent cross-examination, the tape recordings were played for the jury, and the jury was told they could disregard the opinion of the voice identification expert.50

Voice identification evidence was admitted by the Sixth Circuit Court of Appeals in United States v. Jenkins 51 using the same logic as in Baller. Here the court said that the issue of admissibility was within the discretion of the trial judge and that once a proper foundation had been laid the trier of fact was able to assign proper weight to the evidence.52

In 1976 the New York Supreme Court pointed out, in the case of People v. Rogers 53, that fifty different trial courts had admitted spectrographic voice identification evidence, as had fourteen out of fifteen U. S. District Court judges, and only two out of thirty- seven states considering the issue had rejected admission.54 The Rogers court stated that this technique, when accompanied by aural examination and conducted by a qualified examiner, had now reached the level of general scientific acceptance by those who would be expected to be familiar with its use, and as such, has reached the level of scientific acceptance and reliability necessary for admission.55 The court also pointed out that other scientific evidence processes are regularly admitted which as, or less, reliable than spectrographic voice identification; hair and fiber analysis, ballistics, forensic chemistry and serology, and blood alcohol tests.56

The Supreme Court of California finally put an end to the see-saw ride of admissibility in that state in People v. Kelly 57 by rejecting admission because of insufficient showing of support. "Although voiceprint analysis may indeed constitute a reliable and valuable tool in either identifying or eliminating suspects in criminal cases, that fact was not satisfactorily demonstrated in this case".58 In this case the court seemed to have the most trouble with the fact the only expert provided to lay the foundation for admission was the technician who performed the analysis, saying that a single witness can not attest to the views of the scientific community on this new technique and that this witness, who may not be capable of a fair and impartial evaluation of the technique since he has built a career on it, lacked the academic credentials to express an opinion as to the acceptance of the technique by the scientific community.59

In United States v. McDaniel 60, it appears that District of Columbia Circuit Court of Appeals would have liked to admit the spectrographic voice identification evidence but had to reject it because the shadow of the Addison decision of two years past "looms over our consideration of this issue".61 The court held the admission of the voice identification evidence to be harmless error in that the rest of the evidence was overwhelming. The court did recognize the trend toward admissibility and contemplated that it may be time to reexamine the holding of Addison "in light of the apparently increased reliability and general acceptance in the scientific community".62

The Supreme Court of Pennsylvania rejected admission in Commonwealth v. Topa 63 holding that the technician's opinion alone will not suffice to permit the introduction of scientific evidence into a court of law.64 This was the same situation, in fact the same single expert, which confronted the Kelly court.

In People v. Tobey 65 the Michigan Supreme Court found, by applying the Frye test, that the trial court erred in admitting spectrographic voice identification evidence. The court found that neither of the two experts testifying in favor of the technique could be called disinterested and impartial experts in that both had built their reputations and careers on this type of work.66 The court pointed out that not all courts require independent and impartial proof of general scientific acceptability and was quick to add that this decision was not intended in anyway to foreclose the introduction of such evidence in future cases where there is demonstrated solid scientific approval and support of this new method of identification.67

In admitting voice identification evidence, the United States District Court for the Southern District of New York, in United States v. Willaims 68, found that the requirements of the Frye test were met when the technique was performed "by aural comparison and spectrographic analysis".69 The court stated that the concerns of the defendant that this technique had a mystique of scientific precision which may mask the ultimate subjectivity of spectrographic analysis, although they were valid concerns, could be alleviated by action other than suppression of the evidence, such as opposing expert opinion and jury instructions allowing the jury to determine the weight, if any, of the evidence.70

In People v. Collins 71, the Supreme Court of New York rejected admission of spectrographic voice identification evidence saying that the Frye test alone was insufficient to determine admissibility and must be used in conjunction with a test of reliability.72 The court found that the proponents of the technique were in the minority and that the remainder of the relevant scientific community either expressed opposition or expressed no opinion.73

In Brown v. United States 74, the District of Columbia Court of Appeals rejected the use of voice identification evidence, but held the error to be harmless and affirmed the conviction in light of overwhelming non-spectrographic identification of the defendant as perpetrator of the crime. One of the main problems in this case was the fact that the exemplar of the defendant's voice was recorded in a defective manner but used anyway after the tape speed malfunction had been corrected in a laboratory. Dr. Tosi, testifying as a proponent of the technique, stated that the technician should not have used the defective recording as a basis of comparison.75 The court held the technique was not shown to be sufficiently reliable and accepted within the scientific community to permit its use in this criminal case, but that this decision did not foreclose a future decision as to admissibility of the technique.76

In the civil case of D'Arc v. D'Arc 77, the court found that the requirements of the Frye test had not been met and thus the evidence could not be admitted. The court believed that even with proper instructions to the contrary, this type of evidence "has the potentiality to be assumed by many jurors as being conclusive and dispositive" and thus should be subject to strict standards of admission.78

The court in State v. Williams 79 refused to apply the Frye standard citing instead the Maine Rules of Evidence, Rule 401, which states "all relevant evidence is admissible", with relevant being described as evidence having any tendency to make the existence of any fact that is of consequence to the determination of the action more probable or less probable than it would be without the evidence.80

In Reed v. State 81 the court applied the Frye standard to determine admissibility with a rather wide definition of the scientific community which included "those whose scientific background and training are sufficient to allow them to comprehend and understand the process and form a judgment about it".82 The court said the trial court erred in using the more restricted definition of scientific community, "those who are knowledgeable, directly knowledgeable through work, utilization of the techniques, experimentation and so forth" and did not mean the broad general scientific community of speech and hearing science.83

In a fifty-one page dissent to the Reed decision 84, Judge Smith points out that the Frye standard is much criticized and has never been adopted in the state of Maryland, that this decision is out of step with other courts on related issues of fingerprints, ballistics, x-rays and the like, that this decision is out of step with prior Maryland holdings on expert testimony, that the majority of reported opinions have accepted such evidence, and that even if Frye were applicable it is satisfied.

In United States v. Williams 85 the court did not apply the Frye standard but did note that acceptance of the technique appeared strong among scientists who had worked with spectrograms and weak among those who had not.86 The court then focused on the reliability of the technique and the tendency to mislead. As to the reliability of the technique, the court noted the small error rate, 2.4% false identification, the existence and maintenance of standards of analysis, and the conservative manner in which the technique was applied.87 As to the tendency to mislead, the court felt that adequate precautions were taken in that the jury could view the spectrograms and listen to the recording and the expert's qualifications, the reliability of the equipment and the technique were subject to scrutiny by the defense, and the jury was instructed that they were free to disregard the testimony of the experts.88

In the case of People v. Bein 89 the court based admissibility on a two pronged test; general acceptance by the relevant scientific community, and competent expert testimony establishing reliability of the process. The court found that both tests had been met and allow the admission of the evidence.90 The court described the relevant scientific community "to be that group of scientists who are concerned with the problems of voice identification for forensic and other purposes".91 The court also suggested that "it is no different in this field of expertise than in other fields, that where experts disagree, it is for the finder of fact to determine which testimony is the more credible and therefore more acceptable".92

The Ohio Supreme Court, in State v. Williams 93, relied on their own state rules of evidence, as did the Maine court in Williams, and rejected the use of the Frye standard. The court refused "to engage in scientific nose counting for the purpose of whether evidence based on newly ascertained or applied scientific principles is admissible".94 The court noted, with approval, the playing of the recordings to the jury and, that the jury was free to reject the testimony of the expert.95

In that same year, right across the border in Indiana, the court in Cornett v. State96 rejected admission of voice identification evidence saying the conditions set out in Frye had not been met. Here the court used a wide definition of the scientific community which included linguists, psychologists and engineers who use voice spectrography for identification purposes.97 Although the court held that the trial court erred in admitting the evidence, the error was found to be harmless and the conviction affirmed.98

Likewise the court in State v. Gortarez 99 rejected the admission of voice identification evidence but affirmed the conviction holding such admission to be harmless error. The court also used a wide definition of the scientific community in applying the Frye standard including experts in the fields of acoustical engineering, acoustics, communication electronics, linguists, phonetics, physics and speech communications and found that there was not general acceptance among these scientists.100

In the case of United States v. Love101, the admissibility of spectrographic voice identification was not at issue. The fourth circuit Court of Appeals was reviewing whether the trial judge's comments about a voice identification expert were considered error. The trial judge told the jury that they, the jury, were to assign whatever weight they wanted to the testimony of the expert and even disregard his testimony if they "should conclude that his opinion was not based on adequate education, training or experience, or that his professed science of voice print identification was not sufficiently reliable, accurate, and dependable."102 The Court of Appeals found no error in the judge's instruction to the jury.

In admitting spectrographic voice identification evidence, the Supreme Court of Rhode Island, in State v. Wheeler 103, declined to apply the Frye standard holding instead "the law and practice of this state on the use of expert testimony has historically been based on the principle that helpfulness to the trier of fact is the most critical consideration".104 The court reviewed the cases around the country, both state and federal, and noted that the majority of circuit courts that have considered admission of spectrographic evidence have decided in favor of its admission.105 The court pointed out that the defendant had all the proper safeguards such as cross-examination, rebuttal experts, and the jury had the right to reject the evidence for any one of a number of reasons.106

In 1987 the Supreme Court of New Jersey again addressed the issue of admissibility of spectrographic evidence in the civil case of Windmere v. International Insurance Company.112 In affirming the judgment of the Appellate Division, the Supreme Court of New Jersey ruled that the Appellate court's affirmation of the admission of the spectrographic evidence by the trial court was improper. The court stated the admissibility of the spectrographic voice analysis is based on the scientific technique having sufficient scientific basis to produce uniform and reasonably reliable results and contribute materially to the ascertainment of the truth 113, a standard the court admits bears "a close resemblance to the familiar Frye test".114 The court relies upon the "general acceptance within the professional community" to establish the scientific reliability of the voice identification process. In reaching a determination of general acceptance, the court on a three prong test which includes; (1) the testimony of knowledgeable experts, (2) authoritative scientific literature, and (3) persuasive judicial decisions which acknowledge such general acceptance of expert testimony.115 The court found that none of the three prongs indicated that there was a general acceptance of spectrographic voice identification in the professional community. The court criticized the proponent experts as being too closely tied to the development of this identification analysis to represent the opinions of the community.116 The court found that the trial court did not undertake to resolve the issue of conflicting scientific literature and they would make no effort to resolve the conflict.117 The court also reviewed the judicial decisions regarding admissibility and found a split among the jurisdictions as to the reliability of the identification process.118

The New Jersey Supreme Court specifically limited its decision in Windmere excluding spectrographic voice identification evidence to the present case. The court stated that the future use of voice identification evidence "as a reasonably reliable scientific method may not be precluded forever if more thorough proofs as to reliability are introduced" 119 and they will "continue to await the more conclusive evidence of scientific reliability".120

The Court of Appeals of Texas in the case of Pope v. Texas121 refused to address the issue of admissibility of voice identification evidence stating that "the overwhelming evidence against appellant renders this error, if any, harmless"122). Justice McClung in his dissenting opinion states that the trial court did err in admitting the voice identification evidence and that the error was not harmless123. He suggests that the Frye test is the proper standard for assessing the admissibility issue and that the "relevant scientific community" should be defined broadly124. When this aspect of the test is so defined the "general acceptability" criterion is not met.

In February of 1989, the United States Court of Appeals for the Seventh Circuit affirmed the decision of the United States District Court for the Northern District of Illinois admitting spectrographic voice identification evidence in the criminal case of United States of America v. Tamara Jo Smith.125 The Seventh circuit now joins the Second, Fourth and Sixth Circuits in affirming the use of spectrographic voice identification evidence.126 The Appellate court used the Frye standard to hold expert testimony concerning spectrographic voice analysis admissible in cases where the proponent of the testimony has established a proper foundation.127 The court noted that this technique was not one-hundred percent infallible and that the entire scientific community does not support it, however, neither infallibility nor unanimity is a precondition for general acceptance of scientific evidence.128 The Seventh circuit found that a proper foundation had been established in that the expert testified to the theory and the technique, the accuracy of the analysis and the limitations of the process.129 The court noted that variations from the norm result in an increase of false eliminations.130 The jury was not likely to be misled in that they had the opportunity to hear the recordings, see the spectrograms, hear the limitations of the process, witnessed a rigorous cross-examination of the expert and could reject the testimony of the expert.131

In United States v. Maivia,132 the United States District Court admitted spectrographic evidence after a four day hearing on the issue. The court examined the various sub- tests of the Frye test and found that spectrographic voice identification evidence met these tests. The court also noted that "inasmuch as the admissibility of spectrographic evidence to identify voices has received judicial recognition, it is no longer considered novel within the Frye test and consequently the test is inapplicable" 133. The court also looked to the Federal Rules of Evidence, specifically rule 403, in deciding the admissibility of spectrographic voice identification evidence.

In affirming the order of the Appellate Division, the New York Supreme Court, in the case of People v. Jeter134, concluded that the trial court was not able to properly determine that voice identification evidence is generally accepted as reliable based on case law and existing literature. The Court stated that the trial court should have held a preliminary inquiry into the reliability of voice spectrographic evidence. In the light of the other evidence, the admission of the voice identification evidence was held to be harmless error in this case.