Removal of a repeated syllable for ease of pronunciation
Wikipedia says:
Haplology (from Greek ἁπλόος haplóos "simple" and λόγος lógos, "speech") is defined as the elimination of a syllable when two identical or similar syllables occur consecutively. The phenomenon was identified by American philologist Maurice Bloomfield in the 20th century. Linguists sometimes jokingly refer to the phenomenon as "haplogy".
The Wikipedia article lists a handful of examples, including:
- probly (colloquial for probably)
- urine analysis > urinalysis
Now, if you'd excuse me, my grandson is asking for a "bana".