See the guide to the treatment of particular words. Unless otherwise noted, we have largely followed the guidance of CHLG or HeliPaD, when available.
Distinguishing pre-verbal adverbs (or other parts of speech) from separable prefixes/particles can be tricky. Our rule of thumb is to see if the historical dictionaries treat a collocation as a prefix. On this criterion, einsteigen is a verb (RP+VB einsteigen)
while hinein steigen is not: (ADVP (ADV hinein)) (VB steigen)
.