The four main Yiddish dialects in Europe were: German (or Western), Polish/Galician (or Central/Mid-Eastern), Litvish (or North-Eastern), and Ukrainian (or South-Eastern).
LitvisherYiddish was spoken by Jews in Lithuania, Latvia, and Belarus (Russia), and in the northeastern Sulwaki region of Poland.
Eastern Yiddish includes three major dialects: Northeastern or Litvish (spoken in the Baltic region, Belarus, and adjacent areas), Mideastern or Poylish (spoken in Poland and other areas of Central Europe), and Southeastern or Ukrainish (spoken in Ukraine and the Balkans).
Harkavy, as other of the early standardizers, regards Litvish as the "leading branch".
YIVO is often seen as the initiating agent in giving phonetic preference to Litvish, but Harkavy's work predates YIVO's and he was not exclusively describing personal preference.