shm-

Damned if I know how, but earlier today, I ended up at the Wikipedia entry dedicated to the shm-reduplication and I was glad to see that it had been expanded considerably since the last time I checked it out. Among other things, the section on origin now cites a paper by Ghil'ad Zuckermann who points out a similar phenomenon in Turkish, the prefix m-, which conveys the meaning of "x and similar things". And that's when it hit me: "ketáb-metáb"! Jiří Osvald's Teheránská hovorová perština (Colloquial Persian of Tehran), one of the thin yet excellent language textbooks published in the 1960s through 1980s by Nový Orient, also briefly mentions this very phenomenon. I'm reproducing the chapter in question in full (note the typically tehruni "nīss" instead of "nīst"):

§ 106 - Ketáb metáb
Opakováním slova se změnou počáteční souhlásky na m se vyjadřuje "něco takového, podobného."
Ketáb metáb nadárín? - Nemáte něco na čtení? (knížku nebo něco takového)
Púl múl mohem níss. - Nejedná se o peníze.


§ 106 - Ketāb metāb
Repeating a word while changing the initial consonant to m expresses the notion of "something like that, something similar."
Ketāb metāb nadārīn? - Wouldn't you happen to have something to read? (a book or something like that)
Pūl mūl mohem nīss. - It's not about money.

So there. Any guess as to which was first, Persian or Turkish?

UPDATE: In the comments below, Etienne provides some more examples from Indo-Aryan and Dravidian languages (thx m8!). I'll just add two Google books hits, the first of which addresses the Dravidian part and the second one provides an extensive treatment of the shm- reduplication in Yiddish and English and similar echo phenomena in languages from Slavic through Turkic all the way to South Asia. Looks like someone has already written that thesis and it's a pretty cool one.