Dictionary of English to English?

There are hundreds of words which are so old that their origins are unknown.

See the related links below.

Yes

Pronounciation may be the difference. In English, all the written letters are pronounced, whereas some letters though written are not pronounced in French.

Generally we refer to the English spoken in the British Isles as "British English," but the distinction could be made between various forms of it: Irish English, Scottish English and English English.