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LinguiSystems Articulation Test (LAT) App
Ages: 3-21   Grades: PreK-Adult

Get results and save money too!  The LinguiSystems Articulation Test (LAT) App for iPad costs $177 less than the GFTA-2. 

Why should I use the LinguiSystems Articulation Test App?

LinguiSystems Articulation Test for iPad
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The LinguiSystems Articulation Test (LAT) App for iPad is intended for use by certified speech-language pathologists to assess articulation disorders.  A comparison study showed no statistical difference when comparing iPad versus paper administration. Click here to read an abstract about this study.

This app is:

  • Convenient—All you need is a LAT test form and the LAT App on your iPad.  The LAT test forms are sold separately for $41.95/pkg. of 20.  Using the test forms meets the requirement of having original documentation in the client's/student's permanent folder. 
  • Effective—The LAT App identifies articulation disorders and screens for Childhood Apraxia of Speech (CAS).
  • Fast—Complete the entire assessment in about 15 minutes.
  • Simple—Touch the screen to isolate the stimulus items and to change scenes.
  • Results Oriented—Enter the student's chronological age and raw score, and the app calculates age equivalency and standard score.
  • Ebook accessible—The complete LAT Test Examiner's Manual, including the stat tables are included in the LAT App

Test Purpose
The LAT App was designed to identify children and young adults with abnormal articulation patterns.  It ensures a thorough examination of all sounds and blends by presenting several sounds more than one time in the same position.  All positions at the word level are tested.

Test results, in combination with the stimulability and intelligibility ratings and a Childhood Apraxia of Speech Screening included with the LAT App, allow the SLP to make appropriate recommendations regarding the type and length of service.  An accurate diagnosis leads to best practice therapy.

The LAT App can also be used to measure progress in therapy.

Test Description
The LAT App consists of five picture plates that assess all the consonant sounds in words, including initial blends.  The vocalic /r/ is tested in multiple contexts.

The Stimulability Assessment, administered immediately after an incorrect production is made, determines if the student is able to imitate a correct production.

The Intelligibility Rating Scale is based on the student's type and frequency of errors in single-word productions and helps you determine the type and severity of the speech-sound disorder.

The LAT App is easy to administer, score, and interpret.

Examiner Qualifications
The test should be administered by a trained professional familiar with speech sound disorders (e.g., speech-language pathologist).

Test Procedures

  • Begin with Plate I, Item 1 regardless of the student's age.  Present each item verbally and administer every item.  Basals and ceilings are not used.  Write the student's response verbatim on the test form.  Allowable prompts are provided for each item.
  • For Stimulability items, test only the sounds in which an error occurred.
  • For Apraxia Screening items, point to each picture and ask the student to say each word three times.

Testing Time

  • 15-20 minutes

Scoring/Types of Scores
A score of 1 or 0 is assigned to each target sound in the stimulus word.  A score of + or - is assigned to sound productions in the stimulability testing.

Total Number of Errors can be converted to:

  • Age Equivalents
  • Percentile Ranks
  • Standard Scores
  • Overall Intelligibility Rating

Discussion of Performance
The Discussion of Performance section found in the Examiner's Manual helps you bridge from assessment to treatment.

Once you've identified the type and severity of your student's disorder, review this section to determine the therapy approach most appropriate for your student.  The Phonological Processing Approaches, Phonological Contrasts Approaches, and Core Vocabulary approach are described in sufficient detail to help you make the determination.

The special populations of Childhood Apraxia of Speech (CAS) and Dysarthria are also addressed in this section.

Standardization and Statistics
The LAT was standardized on 3,030 subjects and an additional 700+ subjects were included in the LAT/GFTA-2 Comparison Study.  These subjects represented the latest National Census for race, gender, age, and educational placement.

  • Reliability—established by the use of test-retest and internal consistency methods for the total test at all age levels.  The median reliability coefficient is .90 and the SEM is 3.39.  The median item homogeneity coefficient is .91.  Reliability tests include:
    • Test-Retest
    • SEM
    • Item Homogeneity (KR20)
  • Validity—established by the use of content validity which indicated the speech sounds selected were those reflective of phoneme development in children.  Contrasted groups and concurrent validity revealed that the test significantly discriminates between typically-developing subjects and subjects with speech-sound disorders.  All of the correlations are significant at the .01 level. Validity tests include:
    • Contrast Groups (t-values)
    • Analysis of Variance (ANOVA)
  • Race/Socioeconomic Group Difference Analysis—conducted at the item and subtest levels.  Tests included Analysis of Variance (ANOVA), Z tests and Chi Square analysis at the subtest level. Race/socioeconomic level were not found to be strong factors.
  • LAT/GFTA-2 Comparison Study—compared performance for the regular education and articulation disorders groups in twelve age categories (3.0 through 8.11).  Results revealed that the LAT:
    • is better than the GFTA-2 in discriminating between individuals with typical and atypical articulation development
    • has better predictive ability than the GFTA-2
    • has a wider range of item difficulty than the GFTA-2
    • scores are generally more accurate than the GFTA-2

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  • According to ASHA (2008), approximately 24% of the six million students served under IDEA Part B received services for speech or language disorders as their primary disability.
  • An articulation test should include colored drawings with vocabulary targets that are high frequency items for young children in order to elicit a spontaneous speech sample (Madison, Kolbeck, & Walker, 1982).
  • Standardized articulation and phonology tests allow the speech-language pathologist (SLP) to show the family and teachers how the child is performing on a given skill in comparison to age-matched peers.  Standardized test scores are necessary to secure payment from third-party payers in both the private and public sectors.  Standardized test results provide justification for enrollment in speech services and information on the most appropriate goals to begin intervention (Tyler & Tolbert, 2002).
  • Children diagnosed with childhood apraxia of speech (CAS) often show difficulty with multisyllabic words, showing inconsistent productions across consecutive trials (Forrest, 2003).
  • Intelligibility is a complex measure and the SLP should audio record both the standardized articulation test and a language sample for later phonetic analysis.  The severity of the child's intelligibility, along with stimulability of targeted phonemes, will help the SLP set appropriate therapy goals (Kent, Miolo, & Bloedel, 1994).
  • A recent survey of SLPs found that clinicians typically evaluate children's speech sound disorders using a standardized test, along with assessing overall speech intelligibility, and trial therapy methods, including stimulability of incorrect phonemes (Skahan, Watson, & Lof, 2007).  The LinguiSystems Articulation Test (LAT) App is a standardized articulation test that allows the SLP to test the child's speech-sound system with a variety of age-appropriate words, and provides opportunities for overall intelligibility estimates and stimulability testing.

The LinguiSystems Articulation Test (LAT) App incorporates these principles and is also based on expert professional practice.


American Speech-Language-Hearing Association (ASHA). (2008). Incidence and prevalence of communication disorders and hearing loss in children. Retrieved May 18, 2010, from

Forrest, K. (2003). Diagnostic criteria of developmental apraxia of speech used by clinical speech-language pathologists. American Journal of Speech-Language Pathology, 12, 376-380.

Kent, R.D., Miolo, G., & Bloedel, S. (1994). The intelligibility of children's speech: A review of evaluation procedures. American Journal of Speech-Language Pathology, 3, 81-95.

Madison, C.L., Kolbeck, C.P., & Walker, J.L. (1982). An evaluation of stimuli identification on three articulation tests. Language, Speech, and Hearing Services in Schools, 13(2), 110-115.

Skahan, S.M., Watson, M., & Lof, G.L. (2007). Speech-language pathologists' assessment practices for children with suspected speech sound disorders: Results of a national survey. American Journal of Speech-Language Pathology, 16, 246-259.

Tyler, A.A., & Tolbert, L.C. (2002). Speech-language assessment in the clinical setting. American Journal of Speech-Language Pathology, 11, 215-220.


Linda Bowers, Rosemary Huisingh


Linda Bowers, M.A., SLP, is a co-founder and co-owner of LinguiSystems.  She is a speech-language pathologist with wide experience serving language-disordered students of all ages.  Linda has keen professional interest in the thinking, listening, and language abilities of children and adults.

Rosemary Huisingh, M.A., SLP, is a co-founder and co-owner of LinguiSystems.  As a speech-language pathologist, she has successfully served the communication needs of school children for many years.  Rosemary is particularly interested in childhood language, vocabulary, and thinking skills.

Minimum System Requirements

Apple iTunes Store

  • iPad Version 6 only
  • English only
  • not compatible with iPod or iPhone

Android/Google Play

  • not available