Before a child can begin speech/language therapy, he/ she has to go through an evaluation process. During this initial evaluation process, the speech-language pathologist (SLP) may give formal and informal assessments. Formal assessments use different standardized tests. These types of tests use set procedures for both giving and scoring the tests. These tests help an SLP compare the results of a child’s performance to that of his/her peers. Informal assessments involve collecting data across situations from interviews, checklists, observations, play-based assessments, and/or language samples. Both types of assessments provide the SLP with valuable information to determine appropriate intervention goals.

A language sample provides a great deal of information on a child’s language abilities and overall conversational skills. Specific language areas include syntax (grammar), semantics (word meanings), morphology (word parts, such as suffixes and prefixes), and pragmatics (social skills). A language sample often consists of 50 to 100 utterances spoken by the child, but it can have as many as 200 utterances. The SLP writes down exactly what the child says, including errors in grammar. Errors in articulation or speech sounds are not recorded.

Collection of these utterances can take place in a variety of settings (i.e., home, classroom, clinic) with a variety of communication partners (i.e., mom, sibling, therapist), and they can cover different conversational topics. The topics can be prompted by a picture, planned play-based activities, or a story starter, like a silly question. Audio/video recording of the session may take place. This allows the SLP to double-check the accuracy of the language sample.

Below is a small (5 utterance) section of a language sample.

Once all of the child’s utterances have been recorded, the SLP can begin to analyze the language sample. The first thing the SLP will do is count the morphemes. Morphemes are the smallest units of language that have meaning. For example, when counting the morphemes in utterance #5 from the sample, the words “I,” “love,” “with,” and “these” count as one morpheme each. “Playing” counts as two morphemes because the child uses the present progressive form of “play” by adding “-ing.” So, in this example, the child makes five utterances that have six morphemes in total.

Once the SLP adds all of the morphemes in the sample, that number gets divided by the child’s total number of utterances. This gives the child’s mean length of utterance or MLU. Comparing this MLU to age equivalent charts is the next step. If the child’s MLU is within his/her age-equivalent range then there is a good chance that his/her expressive language skills are developing typically. The child’s MLU is the first, most basic bit of information that an SLP obtains from a language sample. Depending on what the SLP wants to look at in the child’s language, there are other ways he/she can continue analyzing the language sample. These specific analyses can provide more information on the child’s syntax, as well as his/her semantics and pragmatics.