A defining feature of Spanish was the diphthongization of the Latin short vowels "e" and "o" into "ie" and "ue", respectively, when they were stressed. Similar sound changes are found in other Romance languages, but in Spanish, they were significant. Some examples:

Peculiar to early Spanish (as in the Gascon dialect of Occitan, and possibly due to a Basque substratum) was the mutation of Latin initial "f-" into "h-" whenever it was followed by a vowel that did not diphthongate. Compare for instance: 

Some consonant clusters of Latin also produced characteristically different results in these languages, for example:

Characterization
భౌగోళిక విభజన
ఐరోపా
వర్గీకరణ, సంబంధిత భాషలు