Core Vocabulary and the AAC Performance Report

High frequency vocabulary or Core vocabulary is the relatively small number of words that constitute the vast majority of what is said in normal communication. With a few hundred words, a person can say over 80% of what is needed (Vanderheiden and Kelso, 1987). Extended, or fringe, vocabulary can be in the thousands or tens of thousands of words that are used infrequently, but constitute the remaining small portion of communication. Core vocabulary typically is consistent from one person to another, across ages, across environments, and across activities. Extended vocabulary typically is specific to particular environments and activities. Total communication requires the use of both core and extended vocabulary.

For people who rely on AAC, appropriate use of core vocabulary is essential to effective communication (Yorkston, Dowden, Honsinger, Marriner, and Smith,1988; Fried-Oken and More, 1992; Baker, Musselwhite, & Kwasniewski, 1999). If use of core vocabulary is low, communication effectiveness is likely to suffer. It is for this reason, that one of the quantitative summary measures of communication included in the AAC Performance Report is use of core vocabulary.

Another related issue is that the most effective communication results from the fastest and most automatic access to the most frequently used words (Hill and Romich, 2000). The core vocabulary of a natural language consists of those words of high frequency that are of general conversational use. Examples of general core vocabulary words would be pronouns, articles, and prepositions. Low frequency or extended vocabulary consists primarily of nouns. To learn more about vocabulary selection for AAC, take the Self-Study Program course on AAC Symbols and Language Representation Methods.

AAC professionals are careful to assure that high frequency words are located appropriately on the AAC system. Further, since access speed can be highly influenced by language representation methods, the fastest methods are used for the highest frequency words (Hill, Holko, & Romich, 2001). One of the appendices of the AAC Performance Report is a frequency order listing of words used in the segmented utterances. This list can be a valuable resource in the planning, implementation, and evaluation of AAC intervention.

The AAC Performance Report includes a General Core Vocabulary (GCV) measure. This is reported as a frequency percentage for core words based on the total number of spontaneously generated words included in the segmented utterances. Methods of calculation for frequency word lists have been documented and routinely used for databases (Tice and Beukelman, 1989; Miller and Chapman, 1991; Hill, 2001).

The individual words are identified through checking for matches with a GCV master list. The GCV list has been created based on a principled assessment and comparison of various vocabulary frequency studies. See references. The list includes all morphological forms of high frequency general use words, even though all forms were not used with high frequency across studies. The GCV master list is in a state of evolution and at the time of this writing has 440 words based on the most current evidence. The GCV list can be viewed at the AAC Institute web site under Products and Services / PeRT / Core Vocabulary and the AAC Performance Report. (Click here to view the list.) PeRT (Performance Report Tool) software facilitates the generation of the AAC Performance Report from LAM (language activity monitoring) data.


Baker, B. R., Musselwhite, C., & Kwasniewski, K. (1999) Literacy, language, and
minspeak: Core vocabulary is the key. Duke University Medical Center, Durham, North Carolina, February.

Fried-Oken, M., & More, L. (1992). An initial vocabulary for non-speaking preschool children based on developmental and environmental language sources. Augmentative and Alternative Communication, 8, 41-56.

Hill, K. (2001). The development of a model for automated performance measurement and the establishment of performance indices for augmented communicators under two sampling conditions. Dissertation Abstracts International, 62(05), 2293. (UMI No. 3013368).

Hill, K., & Romich, B. (2000). AAC core vocabulary analysis: Tools for clinical use. In Proceedings of the RESNA 2000 Annual Conference. Orlando, FL: RESNA Press.

Hill, K. J., Holko, R. & Romich, B. A., (2001, November). AAC performance: the elements of communication rate. Presented at the 2001 ASHA Annual Convention, New Orleans, LA.

Miller, J. (1981). Assessing language production in children: Experimental procedures. Needham Heights, MA: Allyn and Bacon.

Miller, J. F., & Chapman, R.S. (1991). SALT: A computer program for the Systematic Analysis of Language Transcripts. Madison, WI: University of Wisconsin.

Tice, R., & Beukelman, D. (1989). Vocabulary frequency analyzer compare software (Research version 1.0). Department of Special Education and Communication Disorders, University of Nebraska, Lincoln, NE.

Vanderheiden, G. C., & Kelso, D. P. (1987). Comparative analysis of fixed-vocabulary communication acceleration techniques. AAC Augmentative and Alternative Communication, 3, 196-206.

Yorkston, K. M., Dowden, P. A., Honsinger, M. J., Marriner, N., & Smith, K. (1988). A comparison of standard and user vocabulary lists. AAC Augmentative and Alternative Communication, 4, 189-210.

Vocabulary Frequency Lists/Studies

Pediatric Vocabulary Frequency List References

Banajee, M., Dicarlo, C. & Stricklin, S. B. (2003). Core vocabulary determination for toddlers. Augmentative and Alternative Communication, 19, 67-73.

Beukleman, D. R., Jones, R. & Rowan, M. (1989). Frequency of word usage by nondisabled peers in integrated preschool classrooms. Augmentative and Alternative
Communication, 5, 243-248.

Marvin, C. A., Beukelman, D. R., & Bilyeu, D. (1994). Vocabulary-use patterns in preschool children: Effects of context and time sampling. Augmentative and Alternative
Communication, 10, 224-236.

McGinnis, J., & Beukelman, D. R. (1989). Vocabulary requirements for writing activities for academically mainstreamed students with disabilities. Augmentative and Alternative
Communication, 5, 183-191.

Wilson, K. D. (1980). Selection of a core lexicon for use with graphic communication systems. Journal of Child Communication Disorders, 4, 111-123.

Adult Vocabulary Frequency List References

Balandin, S. (1995). The topics and vocabulary of meal break conversations. Unpublished doctoral dissertation, Macquarie University, Sydney.

Balandin, S., & Iacono, T. (1998). A few well-chosen words. Augmentative and Alternative Communication, 14, 147-161.

Berger, K. (1967). The most common words used in conversation. Journal of Communication disorders, 1, 201-214.

Beukelman, D. R., Yorkston, K., Pobleto, M., & Naranjo, C. (1984). Frequency of word occurrence in communication samples produced by adult communication users. Journal
of speech and Hearing Disorders, 49, 360-367.

Mein, R., & O’Connor, N. (1960). A study of the oral vocabularies of severely subnormal patients. Journal of Mental Deficiency Research, 4, 130-143.

Stuart, S., Vanderhoof, D., & Beukelman, D. (1993). Topic and vocabulary use patterns of elderly women. Augmentative and Alternative Communication, 9, 95-110.

Stuart, S., Beukelman, D. R., King, J. (1997). Vocabulary use during extended conversations by two cohorts of older adults. Augmentative and Alternative
Communication, 13, 40-47.

General Population Vocabulary Frequency List References

Howes, D. (1966). A word count of spoken English. Journal of Verbal Learning and
Verbal Behavior, 5, 572-604.

AAC Vocabulary Frequency List References

Beukelman,D. R., McGinnis, J. & Morrow, D. (1991). Vocabulary selection in augmentative and alternative communication. Augmentative and Alternative Communication, 7, 171-677.

Hill, K. (2001). The development of a model for automated performance measurement and the establishment of performance indices for augmented communicators under two
sampling conditions. Dissertation Abstracts International, 62(05), 2293. (UMI No.3013368)

Yorkston, K. M., Dowden, P. A., Honsigner, M. J., Marriner, N., & Smith, K. (1988). A comparison of standard and user vocabulary lists. Augmentative and Alternative Communication, 4, 189-210.

Yorkston, K. M., Honsinger, M. J., Dowden, P. A., & Marriner, N. (1989). Vocabulary selection: A case report. Augmentative and Alternative Communication, 5, 101-108.

Yorkston, K. M., Smith, K., & Beukelman, D. R. (1990). Extended communication samples of augmented communicators I: A comparison of individualized versus standard single word vocabularies. Journal of Speech and Hearing Disorders, 55, 217-224.