A 'substitute' is a linguistic form or grammatical feature which, under certain conventional circumstances, replaces any one of a class of linguistic forms.
- Bloomfield (1935), Pag. 247

The substitute differs from from an ordinary linguistic form, such as 'thing', 'person', 'object', by the fact that its domain is grammatically definable.
- Bloomfield (1935), Pag. 247

In every language we find certain forms, 'substitutes', whose meaning consists largely or entirely of class-meanings.
- Bloomfield (1935), Pag. 146

In their class-meaning, substitutes are one step farther removed than ordinary forms from practical reality, since they designate not real objects but grammatical form-classes [...]
- Bloomfield (1935), Pag. 250

[...] substitutes are, so to speak, linguistic forms of the second degree.
- Bloomfield (1935), Pag. 250

In their substitution-type, on the other hand, substitutes are more primitive than ordinary linguistic forms, for they designate simple features of the immediate situation in which the speech is being uttered.
- Bloomfield (1935), Pag. 250

The substitute differs from an ordinary linguistic form, such as 'thing', 'person', 'object', by the fact that its domain is grammatically definable.
- Bloomfield (1935), Pag. 247