marten / martin are similar-sounding terms with different meanings (referred to as homophones). To better understand the differences, see below for definitions, pronunciation guides, and example sentences using each term. 👇
marten: (noun) agile slender-bodied arboreal mustelids somewhat larger than weasels.
martin: (noun) French bishop who is a patron saint of France (died in 397). (noun) United States actor and comedian (born in 1945). (noun) United States actress (1913-1990). (noun) United States singer (1917-1995). (noun) any of various swallows with squarish or slightly forked tail and long pointed wings; migrate around Martinmas.
marten: m·AA·r·t·ah·n
martin: m·AA·r·t·ah·n
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)