Haplology (from Greekhaplóos "simple" and lógos, "speech") is defined as the elimination of a syllable when two identical or similar syllables occur consecutively. The phenomenon was identified by American philologistMaurice Bloomfield in the 20th century. Linguists sometimes jokingly refer to the phenomenon as "haplogy". As a general rule, haplology occurs in English adverbs of adjectives ending in "le", for example gentlely > gently; ablely > ably.
tataq?tal?na () > taq?tal?na () 'you are fighting each other'
*?a?kulu (*) > kulu () 'I eat'
Spanish: impudicicia > impudicia 'lack of modesty' (i.e. the nominal form of impúdico, "immodest")
The reverse process is known as dittology. It is less common but encountered in some languages. For instance, in the Northern Kurdish or Kurmanji, numerals "du" ('two, 2') and "sê" ('three, 3') undergo a dittological prosess when used in counting:
^U. Pani Shad et alii (1971). "Glossary of linguistic terminology". In Zwicky, Arnold M.; Salus, Peter H.; Binnick, Robert I.; Vanek, Anthony L. (eds.). Studies out in Left Field: Defamatory essays presented to James D. McCawley on his 33rd or 34th birthday. Linguistic Research. p. 125.CS1 maint: uses authors parameter (link) Reprinted as: U. Pani Shad et alii (1992). "Glossary of linguistic terminology". In Zwicky, Arnold M.; Salus, Peter H.; Binnick, Robert I.; Vanek, Anthony L. (eds.). Studies out in Left Field: Defamatory essays presented to James D. McCawley on his 33rd or 34th birthday. John Benjamins. p. 125. doi:10.1075/z.63.CS1 maint: uses authors parameter (link)
^Trubetskoy, N.S. (1969). "Appendix II: Thoughts on Morphonology". In Baltaxe (transl.), Christiane A. M. (ed.). Principles of Phonology. Berkeley and Los Angeles: University of California Press. p. 305. ISBN0-520-01535-5. By morphonology or morphophonology we understand, as is well known, the study of the utilization in morphology of the phonological means of language. Translated from the German (Grundzüge der Phonologie, Prague, 1939).
^Oxford English Dictionary (online version ed.). November 2010.