What semantic functions do they perform (manner, place, direction, time, degree, etc)?

Identifying relations: the semantic functions of wh-clefts in English.

The three grammatical states have distinct syntactical and semantic functions:

The structural and semantic functions of the markup remain identical in each case.

The second thing happening is not so much etymological as sociological: a continuing evolution in semantic function.

Formal transitivity is associated with a variety of semantic functions across languages.

The *-t suffix also occurs in Old Chinese, but its semantic function is unclear.

Some semantic functions of reduplication in various languages.

The precise semantic function of the d-prefix is unclear.

Reduplication has a fairly wide range of semantic functions in Paamese and can in some cases even change the class which a form belongs.