Spanish word with one letter added, changed or missing

[Maciamo]

Mutations are not exclusive to genes. Languages mutate too and often in a similar way as genes, with just single letter changes (like SNPs in genetics). This happens because humans aren't perfect. They mishear words or mispronounce them. It was all the more frequent before universal education and before languages acquired codified, fixed spellings.

When linguists created the spelling rules of modern Romance languages, they usually used the Latin etymology of words to reshape the new standardised language. Standard Italian bears striking similarities to Latin spellings, unlike Italian dialects that evolved more freely.

In contrast French pronunciation has changed so much from Latin that when French académiciens had to decide on the standard spelling of words, they had to add many silent letters to keep as much resemblance as possible to the Latin root of words. This has become a nightmare for learners of French, be them native or foreign, as the written language bears little similarity to the spoken one. English is in a similar situation.

Spanish may be a phonetic language (it is written exactly as it is pronounced), but that did not prevent it from undergoing mutations before its spelling was codified. I have made a list here.

Spanish	French	Italian	Latin
alimaña	animal	animale	animālia
ancla	ancre	ancora	ancŏra
ausentarse	s'absenter	assentarsi	absentare
bendición	bénédiction	benedizione	benedictiōne
blandir	brandir	brandire
cautivar	captiver		captare
desear	désirer	desiderare	desiderare
disminuir	diminuer	diminuire	deminuĕre
ensayar	essayer	(assaggiare)	from exagium
escolta	escorte	scorta	(from Italian)
honrar	honorer	onorare	honorāre
invertir	investir	investire	investire
mensaje	message	messaggio	missaticum (from missus)
nombrar	nominer	nominare	nomināre
oso	ours	orso	ursum
peluca	perruque	parrucca
poseer	posséder	possedere	possidère
postrado	prostré	prostrato	prostatus
propio	propre	proprio	proprio
quebrar	crever	crepare	crepāre
reclutar	recruter	reclutare	(from French)
rendición	reddition	resa	redditio
retaguardia	-	retroguardia	(from Italian)
sentarse	s'asseoir	sedersi	sedere
soplar	souffler	soffio, soffiare	sufflāre
temblar	trembler	tremare	tremulāre

By category:

• Added 'n' : bendición, mensaje, rendición, sentarse
• Other additional consonnant : disminuir, nombrar
• Missing 'r' : desear, oso, postrado, propio, quebrar, temblar, retaguardia
• Shift from 'r' to 'l' : ancla, blandir, escolta, peluca, reclutar
• Shift from 'b' or 'p' to 'u' : ausentarse, cautivar
• Consonnant replaced by another : alimaña, invertir, soplar

[MOESAN]

Spanish show us a tendancy that was even stronger in Oil French; but here you can see some of the current French words are words remake from Latin - among the more evident Spanish tendancies -
the r to l shift is frequnt in Spanish (Castillan to be precise), but it occurs elsewhere (indialects for the most, not always).
the implosive -p, -b changed into -u < -w < -v before explosive is natural enough, spite it doesn't occur frequently elsewhere.
the loss of a liquid (r, l) in a word where one of these sounds occurs also in another syllabe, is not so rare.
All that shows us (I think), Castillan, so the Spanish language, spite official, has not been submitted to the dramatic artificial archaising (re-Latinisation) as has standard French has been! So many genuine Oil French words has been replaced along history.