It depends on the target audience and its country.

I noticed that France’s French press use French version of words more often than in Belgium or Switzerland.

However in Canada (Quebec), French is so protected that using English version of word is sometimes prohibited. A business partner explained me that he wasn’t able to use English words in his commercial publications, including his company name!

I personnaly don’t care as long as the information can be received by a maximum number of people.

The situation is confusing only for a very limited numbers of words (e.g.: un portable is a phone in France and a PC in Switzerland), for which native speakers are well aware. They will correct almost automatically without even noticing.

As for which is more common, it depends on the specific pair of words. For example, I don’t think native French words for “chewing-gum” and “shampooing” even exist. On the other hand, “ordinateur portable” is much more common than “laptop”, which is also used.

My guess is that there are more Anglicisms in more casual registers, but I don’t know to what extent.

There is, however, a difference depending on different national varieties of French. French Canadians are much more likely to say “courriel” than the people of France, for example. Then again, French Canadians have their own set of anglicisms, of course.

Finally, as for which is more “acceptable”, I think this is totally subjective (maybe even meaningless!) and not really the type of question that I think it makes sense to discuss on this site.

La réponse est très différente suivant les pays.

La France a tendance à être chauviniste et statique. Lorsqu’un concept nouveau apparaît, il commence par y avoir de la résistance à l’adoption d’un mot nouveau, qu’il soit ou non d’origine anglaise. Forcément le terme anglais commence à être utilisé. Ensuite, une francisation officielle ou un terme dérivé indépendamment apparaît, mais il est peu adopté. Exemple : tout le monde écrit « CD-ROM » et prononce « cédérome ». Pour le courriel, le terme a pris un peu, mais « email » (prononcé « imeyle », « imèle », « émail » ou quelques autres variantes) ou « mail » (prononcé « meyle », « mail » ou autres variantes) se disent et s’écrivent souvent. Par exemple, sur le site du Monde, on trouve quelques « cederom » mais beaucoup plus de « CD-ROM » ; il y a surtout des « email » et des « e-mail » mais aussi quelques « courriel ».

Le Québec a tendance à beaucoup plus vite franciser un terme anglais, tantôt en adoptant le mot, tantôt en imitant la structure. « Courriel » en vient d’ailleurs.

Je pense qu’il faille faire attention car des mots anglais se retrouvent dans certains dictionnaires français à tort. Par exemple, si je me souviens bien, le mot “ferry” se retrouve dans “Le Petit Robert”, alors qu’un mot plus qu’adéquat existe, soit “traversier”.

Aussi, ce n’est pas parce qu’un mot est utilisé qu’il est bon. Pour utiliser l’un de vos exemples, “cédérom” est probablement un des mots les plus aberrants qu’il puisse y avoir. Le bon mot est “disque compact”, et on laisse tomber la partie “ROM” car il n’y a pas vraiment d’acronymes reconnus pour la “Read-only memory” (mémoire morte) en français.

“Formal use” in France (not necessarily French-speaking countries) has a very specific tie to the Académie Française and its recommendations (as well as a few other institutionalised references for grammar, syntax etc. such as Grevisse).

As such, if you want to be in full conformity with the official French standard of French (and people who write in newspapers or textbooks usually want to), you follow the recommendations of the Académie, which has historically (over the past few decades, at least) gone with the strange habit of forcefully “frenchifying” the spelling of English neologisms, resulting in abhorrent (imho) French neologisms such as “mêl”.

As pointed above, other countries (OK: mostly Québec) with a vested interest in preserving the perceived purity of their practice of French have adopted different localisation strategies, such as translating the concept, rather than the transliterating the word (e.g. “couriel” for “mail” instead of Franco-French “mêl”, which makes considerably more sense, at least).

At the end of the day, this falls down to the usual prescriptivism vs. descriptivism debate. And while the norm in France leans firmly toward the former (Académie Française oblige), many educated people will step in to defend the latter approach as well.

The examples you give are technical, computer-related, words (which typically make the bulk of neologisms these days) and I think there is a strong professional bias amongst IT/computer-proficient people in France toward using unmodified English spelling, perhaps having to do with a higher English proficiency. In such circles (including in corporate contexts), using a spelling like “cédérom” instead of “CD-ROM” would make you sound somewhat “dated” or computer-illiterate, rather than formal (OK, using the word CD-ROM probably will do that anyway, but that’s another issue entirely…).

As the others said, it’s very region-dependent.

In the specific case of Belgium, we tend to use the English words more easily and find the forced French versions a bit silly (“butineur” for browser, “bolidage” for tuning,…) and that’s when we even know them. The main reason for that is because we have to co-exist with Dutch speakers, and dutch adopts foreign words much more easily (albeit in a strange fashion sometimes).

Comme les autres l’ont dit, cela dépend fort des régions.

Dans le cas de la Belgique, les Belges ont tendance à utiliser plus facilement les mots anglais et à trouver les versions francisées un peu bizarres (Sérieusement, un « butineur »??). La principale raison est l’influence des néerlandophones, vu que le néerlandais intègre plus facilement des mots d’origine étrangère.