I bought this phone for my elderly mother, having bought a similar but later version for my father,[the TTfone TT002] which was very successful. I would have bought the same one for her, but wanted them to look slightly different from each other. This phone, TTfone TT099 has pretty much the same features, [good!] but there's a big problem with the keyboard lock: the keyboard locks itself automatically when not in use, and the unlock key on the right hand edge of the phone is the sort you just press. My mother simply can't get the hang of nothing happening when she tries to use the keyboard, and having to press a key and look on the screen to see if the keyboard is unlocked before she does anything, is too hard for her.
The later phone, TT002, has a slider key for manually locking/unlocking the phone, which can't be pressed accidentally, and is much better as it can just be left unlocked and they can forget all about it. If their pocket rings someone, so be it! I have had to buy another TT002 for my mother instead of the TT099.
In both cases, I find the voice & various other sound alerts irritating, and it seems they can't be turned off, however, my parents don't seem to mind, and perhaps they are helpful.