Who are the main reformers of 19th century that attempted to build a methodology around observation of child language learning?

1 Losanov
2 Gouin, F.Franke
3 A.Meillet, C.Bally, S.O.Kartevskii
4 Aristotle, Spinoza, Potebnia
5 L.V.Shcherba, P.V.Bogatyrev, E.D.Polivanov