The brevity law (Zipf's law of abbreviation): More frequent words tend to be shorter
This need not be true in your language, but it's a reasonable law for any communication systems
Some languages have minimal word requirements, e.g. according to Van Urk (lecture notes) nouns and verbs in Imere must have three syllables
This is arguably related to stress (primary stress falls on the antepenultimate syllable in Imere)
Concatenative morphology
Non-concatinative morphology
(from Arkadiev 2020)
Morpholological processes create related words
Allomorphy: The same morpheme might be relalised differently in the same paradigm
An extreme case of this is suppletion, e.g.
Allomophy may involve phonologically conditioned alternations, e.g.
See Odden 2005 for more examples
Arguably many phonological rules apply to solve phonetic/phonological issues (e.g., neutralise in perceptually less contrastive positions, break consonant clusters, etc.)
The phonological change tends to be minimal
Impossible morphophonological rules:
Your language can obey or disobey the brevity law
Your language can be morphologically simple or complex
You'll be asked to make some words and morphemes before Week 5