"th" can still have several different sounds depending on accent and word. The more obvious are t' ie the northern english eg t' mill (its quite hard to write

"th" can still have several different sounds depending on accent and word. The more obvious are t' ie the northern english eg t' mill (its quite hard to write down for those unacquainted with it). Then, of course we have t'ing for thing in some areas. Often the th in that becomes closer in sound to f when compared to the th in this. I personally have a slightly varied accent that generally homes in on RP and I can make "th" sound quite distinct in different words and contexts from a hard ending to "the" to something sounding similar to "fee" (also "the"). The above variations are in a tiny subset of en_ and across a probably tiny piece of time. Nowadays we have phones and TV etc which I think probably works towards homogenising our vocalisations. I suspect that Old English was a bit more complex than is generally thought, if care is not taken.