How does the audience impact how Frederich Engels and Karl Marx present their ideas?

The intended audience of the communist manifesto were urban workers. Because the manifesto was first published in German, the more specific audience were German urban workers. Germany was industrializing very fast at the time, so the potential audience was quite large.

Because the working class is not necessarily as intellectual as a doctor in philosophy like Karl Marx was, or a successful businessman and writer like Engels, the language that Marx and Engels use in the manifesto is clear, simple, and the main intention is to explain, briefly and clearly, their ideas about society, about the economy, and about the situation of the working class and their relationship with the capitalist class.

Because it is a manifesto, its main goal is to promote an idea, and an action: the idea was that capitalism is a mode of production that exploits the working class, and therefore, is unfair, and the action was the mobilization of the working class against capitalism, and for the promotion of another social system (first socialism, then communism).

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there are indirect ways of affecting state laws   by with holding funding's. and that's why we have a 55mph speed on the high way with a design of 70mph speed.