What is the difference among root, stem and base in English word-formation? Possible answer provided to check

Question

Is the following text correct and updated?? It is based on Bauer (1983) but I don't know if this may have changed recently. Thanks in advance!

A root is the primary lexical unit of a word which is not further analysable, either in terms of derivational or inflectional morphology. For example, in the word ‘untouchables,’ the root is ‘touch’.

The part of a word that remains after every inflectional morpheme has been removed is called a stem. Thus, it may still contain derivational affixes. Following the example given before, in the word ‘untouchables,’ the stem is ‘untouchable’ because we have just removed the inflectional morpheme -s that marks the plural. On some occasions, roots and stems have the same form. For example, in the word ‘touched,’ ‘touch’ is the root because it is irreducible into more meaningful elements, but it is also the stem because it is the part remaining after the inflectional morpheme -ed (indicating past tense) has been eliminated.

Likewise, these terms are often confused with that of base. A base or base word is a unit to which derivational or inflectional morphemes can be added. This means that any root or stem can be bases. For instance, in the word ‘untouchables,’ we may find two bases: ‘touchable’ can act as a base to obtain ‘untouchable’; and ‘touch’ can act as a base for creating ‘touchable’.

Answer 1

Like all technical terms, these are metaphorical.

Stem and root are transparently plant terms, and a base is what something is constructed upon, either by nature (the base of the hill), or by human effort (the base of the drill press).

The use of stem and root goes back to classical studies. Latin grammarians gave each verb a single root, with (usually) several stems, each appropriate to a particular use. Each stem proceeded from but differed from the root, as a plant stem does from a plant root. Mostly the stems are formed by affixes, which adds to the metaphor.

Thus, consider the following Latin verbs (given in their principal parts)

1. amō, amāre, amāvī, amātus 'love' (lit, 'I love, to love, I('ve) loved, loved'
   These have a "thematic vowel" ā, that shows up often, and suffixes -re (infinitive), -vi (first person singular perfect tense), and -tus (singular masculine nominative perfect passive participle). The root, common to all forms, is am(ā)-. The present stem is amā-, the perfect stem is amāv-, and the participle stem is amāt-. These are all regular. Latin verbs with this thematic vowel are almost all regular.

2. videō, vidēre, vīdī, vīsus 'see'
   These have a thematic vowel ē, and also lengthen the i in the root to long ī in the perfect and participle stems, and change the d in the participle to s. The 1sgPerf suffix is plain -ī, not -vī. Here the participle stem is vīs-, the perfect stem is vīd-, and the present (and infinitive) stem is vid(ē)-. The root is vid- (with short i). This is not so regular as the first verb.

I could go on, but you see how it goes. Root and stem is a very good metaphor for I-E languages, because of the way they use suffixes. Base seems to me to be a general term that isn't very carefully defined because it's always part of a whole construction or system in which it has a special sense. It's not a term I'd use outside a theory.