@Happy Atheist
[checkmate screams in his pillow]
Please, please bury the idea of one language coming "from" another one as deep as possible, never to be raised again.
Yes, French, Spanish, Portuguese, and - of course - Italian are all Romance languages, but they do **not** "come from" Latin. They have close, common roots with Latin and secondary, recursive influences from Latin, but they are not direct derivatives.
And Celtish languages, in turn, did not "come from" "the" Indo-European language. There's no such thing as "the" Indo-European language and never was. The whole romantic idea of the one, single, original fountain of an Indo-European "Ursprache" died a long time ago. The exact complexity of the whole thing will most certainly never really be fully unveiled.
The main strains of Centum and Satem are about the end of the line. Even they are not a clean cut. And our (very late) alphabet doesn't help much. e.g.: German Hund (hound) and Latin canis are directly related, although they do not "come from" one another in any way; they have a very distant common origin. The initial consonants h and c both have a common root, which is different from other h sounds in German or c sounds in Latin and can be found - in yet another form - in Satem words. Over time they assimilated with other sounds and each came to be represented by the letter h or c in the alphabet, which started being used long after the phonetic assimilation had taken place.
Similarities in vocabulary, such as Latin rooted words in English, are relatively meaningless and usually have nothing to do with the genesis of a language. Lehnwörter ("loan words") happened in ancient times and are still happening today. In fact, most of the words in English we like to attribute to Latin actually came to English much later via French.
Isolated languages, as mentioned by pyro above, are something different altogether. These are not only isolated in their origins, they also are almost always agglutinating in their form, i.e. they use only unchanging roots with prefixes aud suffixes. Common isolated languages in Europe are e.g. Basque and Finno-Hungarian.
The OP is a total idiot.
For a ***very*** good article on the origins of writing. see this: Schmandt-Besserat's thoery of tokens is now bascially universally accepted in the scholarly community.
Trivia: English and Arabic both have a "dark" l sound, while I'm not aware that any other language uses it. ("light" l, as in "Billy"; "dark" l, as in "ball" - if you want to pronounce "Allah" correctly, use a dark l)