Inflectional morphology concerns the combination of stems and affixes where the resulting word has the same word class as the original and serves a grammatical or semantic purpose that is different than the original but transparently related to the original. For example "walk" and "walking". Inflectional morphology in English is fairly simple, and approaches that work in English will not work for all other languages. However, English does have some irregular nouns (geese as plural of goose) and verbs.