Where does “Allgemeinsprache” come from?

Allgemeinsprache (German) comes from German allgemein, from German All, from Middle High German āl, from Old High German āl, from Proto-West Germanic all, from Proto-Germanic allaz, from Proto-Indo-European h₂él- — to grow, nourish.

Ancestry of “Allgemeinsprache”, step by step

Allgemeinsprache traces back through two separate lines of ancestry.

via German allgemein

StepLanguageWordMeaning
1Germanallgemeingeneral (common, basic, usual), universal
2GermanAllcosmos
3Middle High Germanāl—
4Old High Germanālall
5Proto-West Germanicallall
6Proto-Germanicallazall
7Proto-Indo-Europeanh₂él-to grow, nourish

via German sprāche

StepLanguageWordMeaning
1Germansprāchelanguage body of words, and set of methods of combining them
2Middle High Germansprāche—
3Old High Germansprāhha—
4Proto-West Germanic*sprākuspeech, language
Every word from Proto-Indo-European h₂él- →Every word from Proto-Germanic allaz →Every word from Proto-West Germanic all →