The Great Vowel Shift wasn’t one cataclysmic event. Vowels and consonants in all languages shift over time, sometimes more dramatically than others. The shift in English took centuries, and is still incomplete in that some dialects preserve older forms. Wikipedia’s ideas on what caused the shift seem unlikely at best.
“Old,” “Middle,” and “Modern” are relative terms, so Old French was spoken alongside Middle English. They’re just convenient ways to divide distinctive phases of a language.
I’m answering this from memory (& before my morning cuppa) so forgive any errors…
Italian- ‘modern’ Italian is simply the most successful of the myriad Italian dialects, I think it developped from the dialect of the central Tuscan region. Some Italian dialects are still mutually un-intelligible. I’m guessing that as the rpinted word became more available writers moved towards a standard version.
French - France too was a number of smaller kingdoms. There were two main language groups, the Langue d’Oc and the Langue d’Oi; there was a similar proccess of gradual standardisation with all but Catalan disappearing as viable languages.
English was different in that it grew by absorbing new invading languages.
The Romance languages form a continuum from Sicily to Belgium and Belgium to Portugal. The official languages are based on the dialects of the capitals, usually. So French is based on the language of Paris, and Italian (which is a more complicated story) on the Tuscan dialect, but people living on the border speak a language between the two. Or used to before massive compulsary education in the standard language. The Italian dialects aren’t dialects of [Tuscan] Italian, they are Romance dialects of / on the Italian Peninsula.
England was unified earlier, and was smaller to begin with, so the main dialects in Britain are English and Scots. Scots didn’t do the full Great Vowel Shift, so they can produce kids’ books like A Moose in the Hoose (~A Mouse in the House).
From what my Language Prof said, it appears that French consisted for several different languages that underwent extremely rapid changes in the Middle Ages. Eventually, with centralized government in Paris, that became the language throughout the country.
From what I have read on the subject, it’s worth noting that “Old French” and “Old Spanish” probably correspond more to Middle English in terms of the simplification of inflection; while Vulgar Latin is probably a closer parallel to Old English.
But to the OP, yes, there were intermediate versions of Romance languages between vulgar Latin and now. None of them correspond exactly to English’s evolution, of course, but one can speak of an artificially-divided chronology, e.g. vulgar Latin -> old French -> middle French -> modern French.
That would be the High German consonant shift, where a whole bunch of consonants were modified in the upper areas of Germany. It’s why we say “apple” and “cat” and the Dutch and Low Germans say “appel” and “kat”, but the High Germans say “Apfel” and “Katze”.
I have seen references to “Middle Spanish”, but these seem to be rather few. Orbilat.com breaks up Spanish into the following periods:
* The Hispano-Romance period
(5th -- 10th century)
* The Old Spanish Period
(10th -- mid 13th century)
* The Middle Spanish Period
(mid 13th - end 15th century)
* The Classical Spanish Period
* The Modern period
One reason that may be a possiblity as to why Spanish is usually divided into two periods than three, is that for the most part, much of Old Spanish is much more comprehensible to a modern Spanish speaker than an Old English text is to a Modern English speaker. There are of course a lot of differences, such as the form “ganades” for the modern form “ganáis”. The Edicto de Expulsion de los Judios (Edict of the expulsion of the Jews), from 1492 is even clearer: http://www.orbilat.com/Languages/Spanish/Texts/01-Medieval_period/1492-Edicto_de_Expulsion.html
By the way, Spanish actually originated in the town of Burgos, north of Madrid. Castilian was also one of those Romance Languages which could be considered peculiar and archaic in some ways. For instance, the word “cuyo” comes from Latin “cuius” and had fallen out of use and had become obsolete in most of the Roman empire by 1st century BC. Likewise, the word “hablar” comes from pre-Classical “fabulari” - “to converse”, where you have parlare in Italian and parler in French.