The writing on the Berlin Wall has changed, from German epithets against "Crazy Russians" to Turkish slogans proclaiming "Freedom Fighters." It is a sign of the unrest stirring in West Germany's Turkish ghettos. It is the voice of the other side of West Germany.

A Turkish school teacher, Celalettin Kesin, bled to death in a street here in Janaury, the victim of gangland-style violence that is on the rise between Turkish political sects. The death heightened fears among West German authorities of further brawling.

Berlin officials reacted swiftly, increasing the police patrols in Turkish neighborhoods and warning that more clashes would mean automatic deportation of Turkish group leaders.

For the moment an uneasy peace has been restored. But the belief persists in official circles that what the newspapers call a "social time bomb" for West Germany is ticking.

West Germany, with no tradition of absorbing vast numbers of immigrants who differ from people here physically and culturally, is not a melting pot. But in recognition of the new need to move in the direction, the West German Cabinet last month decided to relax naturalization requirements and improve social programs for the immigrants.

There are 4.1 million foreigners living in West Germany today, most of them swept here from southern Europe in a migratory wave of workers actively recruited by Western European countries to cover labor shortages in the 1960s and early 1970s. Foreign workers and their families in West Germany comprise about 7 percent of the total population and about 12 percent of the entire labor force.

They have taken many of the jobs the West Germans do not want, the menial chores. Even that classic of German autos, the Volkswagen, is frequently made by Turkish and Yugoslav workers on assembly lines where the portion of foreign workers runs as high as 85 percent.

The problem of social integration, complicated by barriers of language and culture, is most evident with the Turks, who represent about one in four foreigners in West Germany. There are 100,000 of them in West Berlin alone.

While most of America's poor are U.S. citizens with constitutional rights and protections, West Germany's foreign workers remain outsiders.

This makes the problem all the more delicate for the federal government and a special test for the social attitudes of the West German population, unaccustomed generally to blending with other ethnic groups.

West Germany makes no pretense of being a melting pot.

"We are not an immigration country," said Gerhard Stegemann, a senior official in West Berlin's Department of Labor and Social Welfare, adding that Germany had no intention of becoming one.

Along with other Common Market countries, West Germany in 1973 banned the hiring of more foreign workers from outside the Common Market. Unemployment at the time was rising in the European Community.

European officials expected the foreign workers who had arrived before the ban to return soon to their native lands. As if to stress the point, the workers were popularily called gystarbeiter, or guestworker.

But the guests have stayed, attracted by West Germany's higher wages and dissuaded from leaving by economic problems at home. Their number has actually increased slightly in the past seven years as family members have been allowed to join the workers already here.

West German officials, who for years had regarded the Turkish community merely as a willing work force not to be assimilated into German society, have gradually accepted the necessity of an integration program.

This change was marked last autumn by the release of a federal study of foreign workers in West Germany that went far beyond previous reports in its recommendations to integrate foreigners.

Last month the West German Cabinet endorsed many of the suggested measures with an aim especially toward easing integration for younger generations of foreigners who grow up in West Germany.

Naturalization requirements for them will be relaxed and special education programs started. In West Berlin, authorities adopted a catalogue of integration initiatives and ordered that 10 percent of all public housing be reserved for foreigners.

But West Germany still lacks a countrywide policy. It will be the responsibility largely of states to implement new federal directives, and there is bound to be foot-dragging, particularly in states led by conservative opposition Christian Democratic Party.

Foreign workers pose a special dilemma for the Germans.

"German society has never been a multiracial one, and there is a lack of wisdom about how to amalgamate," said Peter Rothammer, a sociologist with Berlin's Institute for Urban Studies.

What integration there is in Germany has occurred at work. Foreign workers have received the right to elect representatives to company work councils, while at the same time lacking the right to elect local community representatives.

But even Turks who become West German citizens complain of widespread and blatant discrimination against them on the job, in the housing market, at school and in discotheques.

"The blond Turk has a better chance here," Hans Joachim Jankus, head of the foreign workers branch of the Berlin police, conceded only halfjokingly.

Authorities, nonetheless, reject the suggestion that antidiscrimination legislation such as the U.S. Civil Rights Act is needed here.

"It is not a question of law but of attitudes," said Sen. Peter Ulrich, who has charge of internal security for Berlin. "What we need are not new laws but new programs."

West German attitudes are only half the story. Turks deeply resist integrating with the Germans. Coming from a culture vastly different in religion, education and the role of women, Turkish families in West Germany often shun Western ways and hold fast to native traditions.

Berlin authorities note that more Koreans have sought West German citizenship than Turks, although there are 50 times more Turks living here.

Standing in the center of the Turkish communicty here -- called "little Ankara" -- it is easy to forget one is in Germany. Streets have been informally given Turkish names and shops purvey flat pita bread, sheep cheese and garlic instead of German wurst, bauernbrot, veal and pig knuckles.

Women wear black veils, the smell of mutton carries through the air and dark-skinned men sit playing board games. There are Turkish banks and Turkish restaurants, Turkish songs playing on the radio and listings in the paper for Turkish dentists, midwives, driving schools and travel agents.

One travel agent is Oncu Gursu, an example of a Turk who found success here. He started here as a student, worked for the consulate general and later in a travel bureau, and today owns six offices in town. But only a relatively few Turks have managed to do so well.

Because West German schools do not provide what they deem proper religious instruction, Turks have set up 133 Islamic centers that offer prayer meetings and teach the Koran. It is at these Koran schools some Germans contend, that Turkish children are taught to hate nonbelievers.

Authorities believe two-thirds of the 18 mosques in Berlin are under the control of political extremist groups that police say are responsible for much of the new militancy. The recent violence is thought by officials to be linked to the general spread of Islamic extremism.

Recent clashes have left many Turks troubled as well.

"Most people here want to have peace," said Yavuz Sevdir, 34, a Turk who runs a recreation center. "We have our kids here and want to stay. We know it is not our country and don't want to cause trouble."

Part of the problem, said Sevdir, is that many Turks arrive in West Germany lacking a good political education and so are easily drawn toward the extremist parties.

The future depends heavily on what kind of employment will be available to younger generations, many of whom refuse to accept the second-class status of their immigrant parents. But most are likely to continue as a new European proletariat, still suffering serious educational handicaps.

There are 12,000 school-age Turks in West Berlin. Language problems make it so difficult for them to keep up with the work requred by German schools that an estimated 70 percent will never complete their studies. Yet without the vital diploma, they will find it almost impossible to get jobs in the skilled trades, even as apprentices.

"The gate has become open for liberalization," said Rothammer. "The question is, will the Turks in the process of gaining more self-consciousness, feel more a part of this country or more a part of themselves?"