Introduction to Morphology

The words in the first group are open class words, the words in the second group are closed class words. 

pheasant (n)                                     me (pron.)
phone (n or v)                                  they (pron.)
fancy  (v)                                           which (pron.)
witter (v)                                            from (prep.)
sheepishly (adv)                              and (conj.)
today (adv)                                       could (aux.)
computer (n)                                     the (det.)
flat (n or adj)                                     since (conj.)
traumatized (adj)                              in (prep.)
shifty (adj)
head out (v)

Open class words are also called content words or lexical words.

• This class of words readily admits new words and new meanings (high change).
• It's a large group of words.
• Made up of monosyllabic, disyllabic and polysyllabic words.
• Verbs in this group are called lexical verbs.

Close class words are also called function words or grammatical words. 

• This class of words doesn't readily admit new words and new meanings (low change).
• It's a small group of words.
• Words are likely to be monosyllabic or disyllabic.
• Verbs in this group are auxiliary verbs.

Now that we've discussed open class words and close class words, let's look at how new words are made.