Phonetic Weakness

Spoken Vulgar Latin favored words that were rhythmically strong and easy to pronounce in casual speech. [1]

• Ignis is short and phonetically distinct, but when inflected in spoken Latin, it could easily be swallowed or confused with other terms.
• Focus (and its accusative form focum) had a strong, punchy consonant structure that easily evolved into the syllabically robust fuoco. [1, 2, 3]