Yes, Logwood. It was expensive. Many academic books are. I found it online for slightly cheaper (on www.abebooks.com), around US$80, which isn't that much cheaper, but I feel it's worth it. As for taf (yes, the final letter in the Hebrew alphabet), I meant the distinction between taf at the beginning of a word, like in torah (with dagesh), and at the end of one, like in bath 'daughter' (without dagesh). In Sephardic they are both pronounced /t/, but in Ashkenazic the first one is pronounced /t/, but the second one is /s/.

Now, who decided that from all of these words

Nobody. Most language change is unpremeditated.

Ceci n'est pas un seing.