未然形 ＋ ふ
This is an archaic verb ending that existed in the oldest attested Nara period japanese. It marks continuation or repetition, very much like modern 〜つづける.
It’s very interesting because a lot of the verbs that it has derived are still being used today even though the ending is no longer productive. The ふ in this case eventually became う in the modern language. It’s a very common thing in world languages for weak aspirated sounds like ふ’s ɸ (a sound best described as half way between h and f which probably originally came from p) to be lost completely, especially intervocalically.
A few examples -
向く ‘to face’ + ふ becomes 向かふ and then modern day 向かう ‘to go towards.’ In other words, to continually face = to go towards.
住む ‘to reside’ + ふ becomes 住まふ. It has a stem usage 住まひ which becomes 住まい ‘residence, address.’ Therefore, to continually reside = a residence.
移る ‘to move’ + ふ becomes 移らふ and then 移ろふ. It is now 移ろう ‘to fade, to change.’ To continually move = to fade, change.
語る ‘to talk, tell’ + ふ becomes 語らふ. It has a stem usage 語らひ which becomes 語らい ‘a talk.’ Therefore, to continually talk = a talk
なる ‘to get used to’ + ふ becomes ならふ and then modern ならう (習う) ‘to learn.’ Therefore, to continually get used to = to learn. Keep in mind also that the original verb なる has become modern なれる (慣れる) due to some verb class shifts (Notably, nidan verbs became ichidan verbs).
The last example is my favorite probably for the fact that 習う is used so often. The fact that it’s derived from a verb you never would have thought it to be related to and it secretly retains a really archaic verbal ending makes me happy. This is why I love historical linguistics and am sad that it’s grandeur has been consistently disregarded in favor of Chomskian malarky.
Whatever the case, I think the ならう example exemplifies the puzzling work that historical linguists do, continually finding past forms and relationships.
I still hold out hope that the history of where the japanese language will some day be revealed. There are some interesting theories out there but none that really hold water. It could very well be that the language family that Japanese derived from has been completely lost with absolutely no records to show.
Currently, I’m very intrigued by the theory in which the precursor to the japanese language existed on the Korean peninsula possibly being a substrate to ancient Korean languages and/or the Goguryeo language and apparently leaving a bunch of japanese-like toponyms on the peninsula. But, of course, I’d like to see more evidence (which as of now there isn’t much of). I’m not entirely convinced that Japanese is derived from Goguryeo itself. I think the derivations I’ve seen from that language are too much of a stretch (Though, of course, the amount of words that we have left from Goguryeo is very small which makes it hard to have multiple strong comparisons) As for Korean, there’s definitely a very strong syntactic relationship between it and Japanese but that’s certainly not enough to show a genetic relationship. That could very well be caused by proto-japanese acting as some type of substrate however. The other theories about being related to Austronesian or being some type of mixed language and the whole Altaic thing are all crap.
That’s not to say that some of the Altaic languages aren’t related but I think it’s probably more of a sprachbund than anything else (with a hefty dollop of chance). Sticking the Japonic languages and Korean into Altaic is really just a copout in my opinion. And all those instances of comparing modern Turkish to modern Japanese just don’t make any type of sense. This kind of thing can be done to find phonological correspondences and what not but the correspondences they’ve found have been pretty awful and there’s too much time and distance in between these two languages if they are in fact related. Definitely more, I must say, than between languages like Latin and Sanskrit.
Well now that I’ve digressed sufficiently I best leave it at that.