Twelve Spanish-speaking kindergarteners livinq in Los Angeles were tested for usage of English verb tense morphemes through responses elicited during task situations that were dramatized with the use of toy-like realia. The children were first asked to provide a constructed response to questions, and were then given model sentences for immediate imitation. For comparison, three English-speaking kindergarteners were similarly tested. A longitudinal follow-up was done at the first-grade and third-grade levels. The data were sufficient to support an acquisition sequence for five auxiliary morphemes. In kindergarten, only the progressive suffix "-ing" was produced to criterion by a high percentage of the Spanish speakers. In first grade, "did" came under control. In third grade, where morphemic tense usage within relative clauses was recorded, perfective "have" and the suffixes "-ed" and "-en" reached criterion in certain contexts ("have" was controlled in negative contexts only, the suffixes in affirmative contexts only), but command of these morphemes was still developing. This finding suggests that phonetic difficulty may initially constrain past-tense marking to a context-sensitive rule, limited to vocalic or sonorant stem-final environments. A bibliography is appended. (JB)