An interesting feature of Brazilian Portuguese is the epenthesis which occurs in consonant clusters. For example, the name Edna is pronounced e-ji-na or e-di-na in those varieties which don't palatalize. "Admirar" (to admire) is a-ji-mi-rar and "advogado" (lawyer) is a-ji-vo-ga-du or a-ji-vo-ga-du if there is no word final vowel raising. The word "psicologia" (the p is pronounced) is pi-si-co-lo-gi-a.
However, in the word "atlantico" (Atlantic) no epenthesis occurs. Why is this? It doesn't seem plausible to treat the "tl" as a syllable initial consonant cluster because it never occurs word initially. The syllable structure appears to be at-lan-ti-co. At first I thought that maybe epenthesis could only occur if the two segments were plosives, but in the case of "advogado" and "psicologia" we have a plosive followed by a fricative. I then thought that perhaps the two consonants had to agree in voicing but no epenthesis occurs in "Brasil" (Brazil) so this obviously could not be the rule.
In comparison to plosives and fricatives, liquids have greater airflow through the oral cavity. In this sense they are rather similar to vowels. In many varieties of Brazilian Portuguese the l is vocalized syllable finally in words such as "sal" (salt), "caldo" (broth) and "Brasil" (Brazil) . The r is often deleted or barely audible when it occurs word finally as in "pensar" (to think) and "mar" (sea). In these cases they function more like vowels than consonants. The l, when it vocalizes, can be treated as +continuant rather than -continuant.
The rule is that consonant clusters are repaired with an epenthetic vowel in those cases where the second segment is not a liquid. "Atleta" (athlete) is at-le-ta and "prato" (plate) is pra-tu. Why does no epenthesis occur when the second segment is a liquid? Perhaps it is because the liquid is +continuant and thus sufficiently similar to the vowel, thereby eliminating the need for epenthesis. Epenthesis must only occur in those environments where the two segments are rather different. Thus the rule for Brazilian Portuguese epenthesis is that the two segments of a consonant cluster are modified by epenthesis if they are two plosives or a plosive followed by a fricative. If the second segment is a liquid, epenthesis is blocked.