Assignment 2:   
Understanding Language Acquisition

Language is among the most remarkable abilities children acquire, and the process of its acquisition is a fascinating story in developmental psychology. The purpose of this project is to understand the process of language acquisition through hands-on observation of children learning to speak.  Completing the project will have four steps: 1) collecting a linguistic corpus, 2) analyzing the corpus, 3) determining whether the child is developmentally behind, developmentally advanced, or right on schedule for his or her age, and 4) writing-up the assignment.  I will describe each of these steps.

1.  Collecting a linguistic corpus
To collect a linguistic corpus, you will need to transcribe 15-20 utterances expressed by a target child.  You may collect the data by listening to any child between the ages of 18 months to 3 or 4 years.  Copy down the conversation verbatim or better still record it and then later transcribes the audiotaped conversation.  Collect 15-20 child utterances, defined as a single expression that communicates a single idea, akin to a sentence.  

Not only will you have to transcribe verbatim what the child says but also what is said to the child. This may be difficult at times, but do your best. In addition you will have to describe the ongoing actions, objects, or events in the context. To code the linguistic and non-linguistic events, get a number of sheets of paper and draw a line length-wise down the center on each one.  On the left side record what was said by your target child (TC) and others (O) and on the right side record corresponding actions, objects or events that are related to what the child is talking about. Noting these actions, objects, and events will help you figure out the meaning of the child’s utterances. 

2. Analyzing the corpus
Once you have the 15-20 child utterances you are ready to analyze the corpus.  The first analysis to be performed will be on your child’s mean length of utterance or MLU. The MLU is a measure of the average number of meaningful units in your child’s utterances.  It is computed by adding the total number of meaning units over the 15-20 utterances then dividing by the number of utterances.  A meaningful unit of speech is called a Morpheme. A morpheme does not necessarily relate to the "words" or "syllables" used in an utterance but to the sounds that carry meaning. Here are examples of the way morphemes are counted.

	       1     1         2            2      1    1    1      1 
1.  My stupid brothers yelled at me this morning:  10 morphemes  (the word endings “s” and “ed” count as separate morphemes).  We will talk about sibling relations later on in the course!

                1  1       1
2. I go bye-bye: 3 morphemes   (bye-bye has one meaning).
	       1     2         2 
3.  He looks unhappy:  5 morphemes   (“s” ending and “un” prefix have their own endings).

           1        1
4.  Allgone milk: 2 morphemes (allgone has one meaning).
 
Once you have the total of morphemes for each utterance average the totals with the number of utterances (total of morphemes divided by the number of utterances) to find the MLU.   For example, using the utterances above, the MLU is (10+3+5+2)  4 = 5

3.  Analyzing a child’s developmental status
You can probably see how MLU measures the complexity of the child’s syntax (the rules governing the correct ways to combine words to express meaning). With an MLU between 1 and 2.5, the child is limited in the rules available to grammatically string words together. Age norms suggest that children with MLUs between 1 and 2.5 are usually less than 30 months. If your child’s MLU is between 1 and 2.5, examine whether his or her expressions fit the textbook account of one-word (p. 243) and two-word utterances (p. 244) to decide whether the child is linguistically advanced, behind or on schedule.  

With an MLU of between 2.5 and 3.5 the child is making the first steps into complex syntax (e.g., Subject-Verb-Object).  Age norms suggest that children with MLUs between 2.5 and 3.5 are between 30 to 40 months.  To assess your child’s developmental status for language (ahead, behind, or on schedule), see if the textbook account of forming a complex grammar fits with your child’s talk. Look for the kinds of grammatical errors described in the textbook (pp. 357-359).

MLU of 3.5 or higher reflects a child expressing compound sentences with a complex set of syntactic rules.  Age norms suggest that children with MLUs higher than 3.5 are about 40 months or older. To assess the status of the older child, see if he or she has some of the linguistic variability and complexity described in the textbook (pp. 358; 461-462).

Once you identify your child’s MLU, you can examine other aspects of his or her language from descriptions in the textbook.  For example, characterize the kind of the vocabulary he or she has (pp. 243-244; 356-357, 461) and his or her (pragmatic) skills to use language to communicate (pp. 242; 359-360; 462).  You can also identify your child’s early language learning style (p. 245) and his or her linguistic environment (pp. 246-247; 360).

4.  The write up
 	Your paper should have 4 sections.  First, describe the TC (age and sex) and the context of the observations (who else is there and what is going on).  Second, present the corpus – the 15 to 20 utterances of the TC along with utterances of others and the descriptions of ongoing actions, objects and events.  Third, present the MLU of the child with information about how it was calculated. Fourth provide an argument of your child’s developmental status, based on your calculation of your child’s MLU and his or her fit with the textbook analysis of other linguistic characteristics.  That is, explain why you think your TC is linguistically advanced for his or her age, behind for his age, or right on schedule.  

The paper should not be terribly long although I am hesitant to give a page minimum or maximum as the transcription may task unknown numbers of pages.  But if you are on page 20 of the paper, it probably time for us to have a chat!  Please email me with questions or confusion you may have in doing this project.