similar to "known group validity". Case histories are examined in order to determine whether those acquirers who encountered any of the three sorts of simple codes described above had more success in second language acquisition, and whether those with less experience with these codes did worse. The standard literature provides surprisingly little information on this issue,¹ other than the Wagner-Gough and Hatch's case histories mentioned above. I will therefore describe one case history, not as definitive evidence for or against the efficacy of simple codes in second language acquisition, but as a sample, an illustrative example of how this sort of data, despite the inevitable confounds and difficulties inherent with self-report, might shed light on this question.

Our subject is S. K., currently a professor of linguistics at a well-known university in Southern California. S. K. has attempted to acquire four different second languages during adulthood, two Indo-European (French and German) and two Semitic (Hebrew and Amharic). We first analyze the two Indo-European language with respect to the amount of simple input S. K. experienced and his relative success (see Table 1).

        Table 1. Interaction with simple codes for subject "S. K."
_______________________________________________________________________
 Target language    Teacher-talk   Interlanguage-talk   Foreigner-talk
_______________________________________________________________________
German                   +                +                   +
French                   +                +                   -
Hebrew                   +                +                   +
Amharic                  -                -                   +
_______________________________________________________________________
    (Details in text.)

S. K. reports that he received a relatively large amount of teacher-talk in both German and French. He attended a class in German as a second language during his entire 10-month stay in Vienna as a music student in his early 20's. The class was conducted entirely in German due to the presence of a linguistically heterogeneous student body. He also experienced a fair amount of teacher-talk in French, during a 1-month course in Paris at the Alliance Francaise, and more recently as a student in the Pucciani-Hamil method in French as a foreign

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