Are inflectional morphemes considered affixes in English?

Question

From what I remember to have learned in SPANISH, which is my mother tongue, affixes just refer to derivational morphemes such as suffixes and prefixes which can change the meaning of words when added to them. For example, agree - disagree (the opposite) or friend- friendly (from a person to a way of doing something).

However, the inflectional morphemes that mark grammatical functions such as tense or number are not usually considered affixes (and therefore suffixes) because they do not add meaning to the resulting word. It is the case of agree - agreed. We just call them inflectional morphemes, but not affixes.

IS THIS THE SAME IN ENGLISH? What I have seen so far is that most sources treat affixes as all prefixes and suffixes, either they are derivational or inflectional morphemes.

In any case, some sources actually specify that affixes are just the units added to a word changing their meaning, i.e. the derivational morphemes (what I think I learned in Spanish).

Which option is more accurate? Thanks in advance!

Answer 1

Wikipedia captures the usual understanding of the term:

Affixes may be derivational, like English -ness and pre-, or inflectional, like English plural -s and past tense -ed.

In this terminology also Spanish inflectional morphemes are considered affixes.

Now I don't speak Spanish, but this also seems to be what the Spanish Wikipedia says:

Los afijos son secuencias lingüísticas que se anteponen (prefijos), se posponen (sufijos) o insertan (infijos) en una palabra o lexema para modificar su significado, bien gramaticalmente (afijos flexivos), bien semánticamente (afijos derivativos).

Answer 2

You have inverted the usual "considered" relation. There is no uncertainty as to what a prefix is versus a suffix. A prefix precedes the root, a suffix follows the root. "Affix" is neutral as to order. So un- is a prefix and -s is a suffix, both being affixes.

"Considering" comes in in classifying the function of morphemes. We consider the prefix un- to be derivational, but the reasons for this conclusion are murky. One is regularity, that derivation tends to be more lexicalized and irregular, at least in English, but of course we do have highly irregular verb inflection in verbs like be, have. A more hard-line claim is that inflection cannot change part of speech, which partially deems that agentive -er cannot be inflectional. There are other rather useless definitions such as that inflection gives you forms of words and derivation gives you new words (how do we determine that "unimaginable" is a new word rather than a form of the existing word "imaginable"?). This strong lack of agreement reduces the inflection vs. derivation distinction to a question of "consideration".