[...] the grammatical element [...] may consist of some modification of the inner form of the stem [...]
- Sapir (1921), a pag.25

Aside from the expression of pure relation a language may [...] be 'formless' [...] The attempt has sometimes been made to formulate a distinction on the basis of 'inner form.'
- Sapir (1921), a pag.124

Chinese [...] has no formal elements pure and simple, no 'outer form,' but it evidences a keen sense of relations, of the difference between subject and object, attribute and predicate [...] it has an 'inner form' in the same sense in which Latin possesses it, though it is outwardly 'formless' where Latin is outwardly 'formal'.
- Sapir (1921), a pag.124