langue d'oïl (English spelling) languedoil

Japanese: langue d'oïl（英語表記）languedoil

...When we simply say French, we often mean this common language, that is, common French. On the other hand, the northern French dialects (French dialects) that date back to Latin are also called langue d'oïl, which comes from the name of the medieval collective name for these dialects, langue d'oïl. In particular, there are regional variants of French as spoken language that differ somewhat from standard Parisian French in terms of pronunciation, grammar, and vocabulary, and that incorporate local characteristics (such as the rolled r pronunciation heard in southern France), and these are sometimes called regional French.

From Languedoc

…In Southern French, the adverb of affirmation (English yes) is called oc, while in Northern French it is called oïl. The former is also called langue d'oc, and the latter langue d'oïl. The name of the Languedoc region comes from this. …

*Some of the terminology that mentions "langue d'oïl" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…単にフランス語という場合，この共通語たるフランス語，すなわち共通フランス語を指すことが多い。一方，ラテン語にさかのぼる北フランス諸方言(フランス語諸方言)はオイル語方言とも呼ばれるが，それは中世期におけるこれらの方言の総称であるオイル語langue d’oïlの名に由来する。特に話し言葉としてのフランス語には，標準とされるパリのフランス語と多少とも発音･語法･語彙（ごい）の点で異なる，その土地固有の特徴(南フランスにおいて聞かれる巻舌のrの発音など)の混入した地域的変種が見られ，それらを地域フランス語と呼ぶことがある。…