The use of function words in 135 essays written by deaf college underclassmen in developmental and credit-bearing English composition classes is described and compared with Standard English (SE) versions of the same essay. If student and SE versions were the same, this was considered mastery; if the student omitted a word, this was considered avoidance; and if the student added a word, this was considered overuse. The deaf students varied from SE more for function than for content words. They demonstrated low mastery of independent clause markers, demonstratives, third-person singular neuter pronouns, and modals related to possibility, but had relatively high mastery of the first-person singular, and some punctuation. These students strongly avoided some dependent clause markers, some demonstratives, the indefinite article, punctuation except for periods and commas, and the modal verbs may, might and should, but greatly overused other dependent clause markers, the second person and third-person neuter pronouns, quantifiers, the verb do, and the modals could and will. They were also more likely to produce run-ons than fragments. Examples of Function Words Use is appended. (Contains 20 tables and 2 figures.)