Believe it or not, I can’t speak to much of this part of the thread. Why speak Latin? Myself, I do it for fun.
But it is a mistake to attribute the practice of coining neologisms for modern phenomena to lonely people who cannot accept that Latin is a dead language, or who just have too much time on their hands. Latin composition about contemporary life was pretty common until quite recently. It is not that Latin was a “read only” language for 1500 year until Carolus Egger came along and started new coinages, it is more that Latin composition nearly died out in the 20th century… and only now has become the province of fanatics like myself. Unfortunately the 20th century is exactly when the need for new coinages increased sharply, making the job a lot harder for people who want to comple useful modern dictionaries.
But there are good reasons to learn to speak and compose in a dead language. I find it so much easier to learn a language when I’m using it actively, for instance. Futhermore it is much more pleasant.
There was the mention above of using Greek roots rather than Latin for new coinages. The reason for this is that Latin was not really very fond of compound words, whereas Greek was practically synthetomanic… er… I mean obsessed with compounds. Thus, when you need a new word for a machine that caries sounds over a distance you call it a “telephone” not a *longisone vel sim. The problem is that as time has gone on and classical education has become rarer and rarer, people have forgotten which roots are Greek and which are Latin… and even when they know, they don’t seem to have any objection to mixing them. This produces forms like television, automobile, homosexual and so on. That’s all well and good for English, but if you know your classical languages it sounds aweful for Latin. Whereas *ipsemobilis is a ridiculous Latin word (I don’t think you will find any words compounded with ipse- but feel free to prove me wrong) autocinetum is a perfectly logical Greek form… and in fact the modern greek word for car just happens to be autokineton! (I should mention though, that it’s now pronounced aftokineto)
Some other notes on modern coinings- if you want to say vodca say vodca. I won’t stop you, though some might. Again, “potio slavica” is a bit silly, but not as bad as it sounds- if you say it to a bartender she’ll know what you mean… well, if she speaks Latin. And if you find a bartender who speaks Latin, please invite me to go clubbing with you. But back to vodca- Classical Latin did indeed pronounce v as our w, but many Modern Latinists use the Church pronunciation, which pronoucnes it as our v. That point is moot here though, as many Slavic languages (e.g. Russian) will pronounce the word that way too. As for televisor, some people do say that, but it makes me cringe, in part because of the mixing of roots, and in part because the -tor/-sor suffix is normally used for (masculine) human agents, and not for machines. There is more I could say about that issue, but it’s borring, so I’ll get to the point- Neo-Latinists will often say “televisorium” to get past that particular problem. (There is also a -trum suffix used in Classical Latin for machines, but it was really quite rare, so it irks me when moderners overuse it for all these newfangled machines we have these days)
Arachne, by the way, was the Greek word for spider before it was the name of the mythological character. Well, not according to the myth itself, but I’m hardly a fundimentalist when it comes to Greek religion 
And as it has already been mentioned, pontifex was a pagan Roman title long before it was borrowed by Christianity. The pope does not make bridges, but early Roman priests apparently did.
Punic was almost identical to Hebrew, and by the way I’m posting (against my will) from a *(&^y web tv unit, so I can’t even edit BEFORE I post this time!
Justin