CHICAGO (AP) _ Once shunned by foreign-language students, German is making a comeback at some schools thanks to the fall of the Berlin Wall and the move to reunifying the two Germanys, educators say.

Though German still takes a backseat to Spanish and French at most high schools and colleges, students are becoming increasingly aware of its value as a possible career tool, said Helmut Ziesle, president of the northern Illinois chapter of the American Association of Teachers of German and a professor at suburban Wheaton College.

There's been a 30 percent increase this year in the number of Wheaton students majoring in German, he said.

''Once Germany's united, its economic role will become more important,'' Ziesle said in a telephone interview Tuesday.

''The more we are aware here how important that is, the more interest we stimulate in the study of German, I think it will help both countries tremendously,'' he said. ''Most Germans know English, but relativley few Americans know German.''

At south suburban Homewood-Flossmoor High School, the expected enrollment in first-year German will be 19 next year, up from 12 this year, said Principal Charles Smith.

The Illinois Math and Science Academy in Aurora will add a second section of first-year German next year, said teacher John Stark.

And the Chicago public school system's German language summer camp in suburban Lake Forest is filled up with 20 students, said David Oliver, coordinator of the Department of Language and Cultural Education for the Chicago Board of Education.

''It's way over what we expected,'' he said. ''Last year we had a problem getting more than eight students.''

''I think it's based on what's taking place in Germany,'' Oliver said. ''I think there's a whole new spirit.''

Before World War I, German was the most popular foreign language in American schools. Both world wars, and especially Nazi Germany, helped change that, Ziesle said.

So did the growth in the number of Hispanic immigrants in this country, which helped give Spanish top-billing, said Sherry Parriott, president of the Southern Illinois chapter of the German teachers association.

In 1985, the most recent statistics available, about 4 million high school and college students were taking Spanish, about 1.5 million were taking French and about 500,000 German, said Helene Zimmer-Loew, executive director of the association. The Cherry Hill, N.J.-based group has about 6,500 members, mostly high school and college teachers.

''The news I've heard from most colleges and universities is that there's been a greater request for German courses,'' Ms. Zimmer-Loew said.