2. Language families E.g., Germanic Proto-Germanic q g p West North East
qgi egi g
High Low Angl.-Fris. Faroese Icelandic Norw., Gothic
g gi gi Swed., Dan.
German Afr. Dutch English Frisian
Working backward from divergent but related varieties we come up with a variety which we deduce was spoken a certain time ago, from which all related varieties stem. e.g. Proto-Germanic. In some cases, proto-forms are attested, e.g. Latin as ancestor to modern Romance family of languages, but in most cases not.
Germanic has relatively shallow time depth: about 2500 years.
Typical elaboration of lineages is 2-3 for families of relatively shallow time-depth such as Germanic (Nichols 1990)