In general, the universal language on the Internet is English, or more exactly a vague collection of languages called "English" because their common origin is the national language spoken in England by the English. That national language has spread over the world, and several variants such as American (US) English, Australian English, etc exist. A great number of people whose native language is none of the variants know English as a foreign language. They typically use a more or less simplified variant, e.g. excluding most of the idioms of British, American, Australian etc English. Of course, they make mistakes, and sometimes the "English" used by people as a foreign language on the Internet is almost incomprehensible to anyone else. In addition, people who use English as their native language do not know how to spell difficult words, since they basically know English as a spoken language.

Thus, roughly speaking, the universal language of the Internet is clumsy, coarse and misspelled "English".

There are exceptions, most importantly national newsgroups in such countries where English is not the native language of the majority. Even in such groups English is used, for instance when people from other countries wish to participate. And a few international groups have a theme like discussing a particular language or culture so that it is natural to assume that the participants have a common language other than English. Moreover, a group which is partly international in the sense of not being purely national might use a language other than English, for instance if the group is intended for people in German-speaking countries.

Is English a suitable universal language?.

Apart from being widely used and known, English is extremely unsuitable as a universal language. There are several reasons to this.

Any national language, i.e. a language which is or was originally the language of a particular tribe or nation, has obvious defects when used for international communication:

• Native speakers of the language are in a quite different position than others. Some people regard this as bad in itself, as contrary to the equality principle, but I think it is practical consequences that make it bad. Native speakers tend to use idioms and rare words and to speak too fast, unless they exercise conscious control over their language - and such control is difficult and unnatural when applied to one's mother tongue. This implies that in oral communication in particular native speakers of English often have worse problems in getting themselves correctly understood than nonnative speakers!
• National languages exist in various dialects and forms - sometimes they are even mutually unintelligible, but the differences always make communication harder. There is usually no standard for a national language, and even if something that can be called standard exists, it is just one form of the language - typically a form that is only used by a minority, and even by it only in a minority of occasions. For a native speaker of a language, it is natural to use one's own dialect, and it is difficult to avoid this entirely; this emphasizes the importance of the above-mentioned problem of native speakers expressing themselves in international contexts.

English is an eclectic language which tends to borrow words from other languages instead of constructing words for new concepts from older words with derivation or word composition. People often say that English has a rich vocabulary as if it were something to be proud of. The richness of the vocabulary results basically from word borrowing and implies that words for related concepts are typically not related to each other in any obvious, regular manner. Word borrowing makes a language more international in one sense, but in the essential sense it makes it less suitable for international communication, since learning the vocabulary is more difficult.