The language acquisition process is associated not only with social and demographic factors but also with the physiological condition of the child, that is, his or her physical ability to perceive and process enough language input. However, even in this case some sociolinguistic variables such as participation in therapies and high quality language input can help the child to cope with his/her problems. This study aimed at an examination of such variables. A sample of 741 German children acquiring German as their first or second language (393 boys, 348 girls, age median 70 months) was recruited for a series of language tests conducted during the school enrolment examination. On the basis of tests on articulation, phonological short-term memory, vocabulary, speech comprehension, and grammar (S-ENS, AWST-R, ETS 4-8), as well as questionnaires for parents, an expert panel classified all test participants as needing or not needing medical help in acquiring German. A subgroup of children (N = 163) was tested twice: at the age of four and a year or two later. In this subgroup, also data from questionnaires for daycare center teachers were available. Predictors for the classification of children as needing or not needing medical help were examined by classification trees, various association measures, and regressions. The most important sociolinguistic variables were related both to genetic factors and the quality and quantity of the language input. The factor " language disorders in the family" played the major role in the cross-sectional part of the study, the factor " need for additional educational help in acquiring German" in the follow-up part.