Monologue about Metathesis:
Metathesis is a sound change consisting of the switching of consonants, vowels, or even syllables. It is moderately common in the world’s languages, particularly in English as the following examples will show. Such switches can occur within neighboring phonemes, or in phonemes found far away from each other.
Such a change can help differentiate your proto and daughter languages, while still keeping the general feel of the word.
There doesn’t seem to be an easily identifiable pattern as to what sounds get switched, so you as a conlanger have some poetic liberty. However, I try to make sure that the new word is easier to say than the proto-word, as I feel that this is the common denominator.
Examples in Natural Languages:
The following examples involve the transposition of an “r” sound within mother and daughter languages. Be advised than many other phonomes and syllables can also undergo metathesis. However, the “r” sound and other “liquids” do appear in a disproportionate number of metathesis changes.
- The Old English bridd to the Modern English bird
- The Latin crocodilus to the Spanish cocodrilo
- The Latin formaticus to the French fromage
Resources:
The Wikipedia arcticle on metathesis is an important read for aspiring or professional conlangers: