Talk:Dosukoi! Kenkyo ni Daitan / Ramen Daisuki Koizumi-san no Uta / Nen ni wa Nen (Nen'iri Ver.)/@comment-131168-20150822200249

I've seen it written this way elsewhere, but is there a reason 念入り becomes Nen'iri with the apostrophe in there, rather than just plain Neniri or even Nen Iri?