フランス語史 内的な歴史
The development of verb-second syntax in Old French (where the verb must come in second position in a sentence, regardless of whether the subject precedes or follows) is probably due to Germanic influence.
The first person plural ending -ons (Old French -omes, -umes) is likely derived from the Frankish termination -ōmês, -umês (vs. Latin -āmus, -ēmus, -imus, and -īmus; cf. OHG -ōmēs, -umēs).
The use of the letter k in Old French, which was replaced by c and qu during the Renaissance, was due to Germanic influence. Typically, k was not used in written Latin and other Romance languages. Similarly, use of w and y was also diminished.
The impersonal pronoun on "one, you, they" – (from Old French (h)om, a reduced form of homme "man") is a calque of the Germanic impersonal pronoun man "one, you, they", reduced form of mann "man" (cf Old English man "one, you, they", from mann "man"; German man "one, you, they" vs. Mann "man").
The expanded use of avoir "to have" over the more customary use of tenir "to have, hold" seen in other Romance languages is likely to be due to influence from the Germanic word for "have", which has a similar form (cf. Frankish *habēn, Gothic haban, Old Norse hafa, English have).
The increased use of auxiliary verbal tenses, especially passé composé, is probably due to Germanic influence. Unknown in Classical Latin, the passé composé begins to appear in Old French in the early 13th century after the Germanic and the Viking invasions. Its construction is identical to the one seen in all other Germanic languages at that time and before: « verb "be" (être) + past participle » when there is movement, indication of state, or change of condition; and « "have" (avoir) + past participle » for all other verbs. Passé composé is not universal to the Romance language family—only Romance languages known to have Germanic superstrata display this type of construction, and in varying degrees (those nearest to Germanic areas show constructions most similar to those seen in Germanic). Italian, Spanish and Catalan are other Romance languages employing this type of compound verbal tense.
The tendency in Old French to use adverbs to complete the meaning of a verb, as in lever sus ("raise up"), monter amont ("mount up"), aler avec ("go along/go with"), traire avant ("draw forward"), etc. is likely to be of Germanic origin
The reintroduction of a vigesimal system of counting by increments of 20 (e.g. soixante-dix "70" lit. "sixty-ten"; quatre-vingts "80" lit. "four-twenties"; quatre-vingt-dix "90" lit. "four-twenty-ten") is due to North Germanic influence, first appearing in Normandy, in northern France. From there, it spread south after the formation of the French Republic, replacing the typical Romance forms still used today in Belgian and Swiss French. The current vigesimal system was introduced by the Vikings and adopted by the Normans who popularised its use (cf Danish tresindstyve, literally 2 times 30, or 60; English four score and seven for 87). Pre-Roman Celtic languages in Gaul also made use of a vigesimal system, but this system largely vanished early in French linguistic history or became severely marginalised in its range. The Nordic vigesimal system may possibly derive ultimately from the Celtic. Old French also had treis vingts, cinq vingts. (cf. Welsh ugain "20", deugain "40", pedwar ugain "80" lit. "four-twenties").