Not, as popularly assumed, named for any romantic qualities, the Romance languages are languages descended from the language of the Romans; namely, Latin.

The most familiar Romance languages are those that are national languages of Western Europe: Spanish, Portuguese, Italian, French.

However there are and have been quite a few 'minority' Romance languages, whether parallel descendants of the original Vulgar Latin or "merely" dialects or offshoots of the major languages. The following is a list of Romance Languages from SIL's Ethnologue.

Per request, major languages are in bold.

English is not a Romance language. It is not descended from Latin, although it has a huge amount of borrowing from Old French, due to historical circumstances (Norman invasions, IIRC). English and Latin are related however; they are both Indo-European languages, whose reconstructed ancestor proto-Indo-European gave birth to a wide range of other languages such as Greek, Sanskrit, and Yiddish.

Ethnologue are quite keen to elevate what some might call dialects to languages. The above classification is misleading as a straight list of languages. The main surviving varieties of Romance language are: Catalan, French, Italian, Occitan, Portuguese, Romanian, Romansch, Sardinian, and Spanish. That is, in addition to the five national languages, there are those of Sardinia, Catalonia, southern France for Occitan (or Provençal), and lastly Switzerland's Graubünden canton for the one that has various names but is noded as Romansch.

Each of these is very distinct from the others. Any other languages shade off or between these. So Galician is intermediate between Portuguese and Spanish, and Aragonese and Valencian are between Spanish and Catalan. Franco-Provençal, spoken around Geneva and the adjoining parts of France, is intermediate between French and Occitan. If these are to be classed as distinct languages then they are ones that are to some extent mutually intelligible with their neighbours. Naturally, local pride makes many communities want to consider their own varieties fully distinct languages.

Their common ancestor is Latin, but their most recent common ancestor is an unwritten variety that may be called Proto-Romance. While writers kept the classical language fixed, the common people (vulgus) kept on evolving variation in their Vulgar Latin, into the time when the dialects began to diverge. Dialectal variations might have appeared quite soon after the Roman occupation of the various lands. The Celtic Gaulish might have influenced what later became French, for example. From perhaps 700, the people of Gaul, Spain, Italy, and Dacia would have lost the ability to understand each other's Latin, or Roman as the common dialects were called.

Vulgar features included the word caballus instead of equus for 'horse', and testa instead of caput for 'head', though the latter was kept for the derived sense of 'chief'. The accusative endings -um and -am and -em changed to -o and -a and -e, and since the difference between long and short vowels was also lost, these endings were now identical with those of the ablative and in some declensions with the nominative. This conflation hastened the end of the case marking system. Cases survive today in Romanian, and survived to perhaps 1200 in Old French.

Another common Romance feature is the use of the plural vos as singular respectful, with tu being reserved for people such as friends and children. See the excellent Vulgar Latin writeup for more detail on the changes.

In addition to being spoken by major states in Europe, the New World colonizations of Spain, Portugal, and France has made them hugely important world-wide, as has the influence of French on English and its subsequent expansion. A large amount of English vocabulary is Romance, either directly from French or from learned borrowings from Latin. In some cases both: chief and chieftain from older French, chef from modern French, capital and decapitate from Latin, and capo from Italian.
