Coding for data compression with large target's symbol set (where the target symbol set is larger than the source symbol set)

For data compression, every codding that I've seen is binary. It means we convert a language with $$N$$ symbol size to a language with $$M=2$$ symbol size. For example, in Huffman coding, the goal is to find a binary coding ($$M=2$$) for English language ($$N=26$$).

If $$M$$ is not equal to $$2$$ and have a value larger than $$N$$, is there any method to find good coding (or optimal coding) for compression? Is there any research for this type of problem?
Is it a right assumption that when the target symbol size is larger, the goal is to find a map from a subset of source symbols to one target symbol?

Both arithmetic coding and asymmetric numeral systems can be done in arbitrary base $$b$$.