[...] we shall [...] symbolize such terms as 'sings' and 'singer' by the formula 'A + b'. The element 'A' may be either a complete and independent word ('sing') or the fundamental substance, the so-called root or stem or 'radical element' ('sing-') of a word.
- Sapir (1921), a pag.25

[...] the grammatical increment, [...] need not be suffixed to the radical element. [...] it may be inserted into the very body of the stem (like the 'n' of the Latin 'vinco' 'I conquer' as contrasted with its absence in 'vici' 'I have conquered'), it may be the complete or partial repetition of the stem, or it may consist of some modification of the inner form of the stem.
- Sapir (1921), a pag.26

The complete grammatical formula for 'cor' is [...] 'A + (0) + (0) + (0)', though the merely external, phonetic formula would be '(A) -, (A)' indicating the abstracted 'stem' 'cord-', the minus sign a loss of material.
- Sapir (1921), a pag.30

The Hupa word 'te-s-e-ya-te' [...] consists of a radical element '-ya-' 'to go,' three essential prefixes and a formally subsidiary suffix. The element 'te-' indicates that the act takes place here and there in space or continuously over space; [...] it has no clear-cut significance apart from such verb stems as it is customary to connect it with.
- Sapir (1921), a pag.68

'Elder' and 'eldest' were at one time the only possible comparative and superlative forms of 'old' (compare German 'alt', 'älter', 'der älteste'; the vowel following the 'old-', 'alt' was originally an 'i', which modified the quality of the stem vowel).
- Sapir (1921), a pag.188