Table: th_sounds
Columns: proto_germanic
west_germanic
old_english
german
dutch

Question: What's the Proto-Germanic when the Old English is /d/?
SQL: SELECT "proto_germanic" FROM th_sounds WHERE "old_english" = '/d/'

Question: What's the Proto Germanic when then German is /s/ or /ts/?
SQL: SELECT "proto_germanic" FROM th_sounds WHERE "german" = '/s/ or /ts/'

Question: What's the Dutch when then Old English is /d/?
SQL: SELECT "dutch" FROM th_sounds WHERE "old_english" = '/d/'

Question: What's the West Germanic when the German is /s/ or /ts/?
SQL: SELECT "west_germanic" FROM th_sounds WHERE "german" = '/s/ or /ts/'

Question: What's the Proto-Germanic when the German is /t/?
SQL: SELECT "proto_germanic" FROM th_sounds WHERE "german" = '/t/'