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’.