Three hypotheses are examined in relation to English copula and negative utterances produced by three native Spanish speakers. The hypotheses are interference, interlanguage and L1=L2, which states that acquisition of a language by second language learners will parallel acquisiton of the same language by first language learners. The results of the study are as follows: (A) In the copula construction, utterances such as "Is a book" probably represent interlingual identifications of the English "it's" and the Spanish "es." They do not appear to be produced by interference from the Spanish syntactic device of subject omission. (B) The acquisition sequence of the English negative by the subjects does not correspond to the "stages" described by Klima and Bellugi for children acquiring English as a native language. This result tends to disconfirm a strong version of the L2 = L1 hypothesis which would claim that the acquisition order in both the first and second language should be the same. (C) It is difficult to say whether acquisition of the negative by the subjects is systematic and developmental because these concepts are not clearly defined in any versions of the interlanguage hypothesis. (D) Two of the subjects evince different strategies in acquiring the negative. (Author/DB)