🔹 Diphthong-Breaking Verbs (Hiatus)

Regla / Rule: These verbs break the diphthong found in the infinitive when the stem is stressed. As a result, the stressed í or ú receives a written accent (envío, actúo, confío, reúno, rehúyo). In the nosotros and vosotros forms, the stress shifts to the ending, so the diphthong is preserved and no written accent is needed. In Rioplatense Spanish, the vos forms also carry the stress on the final syllable (enviás, confiás, actuás, guiás), while verbs ending in -ir follow the regular voseo pattern (reunís, rehuís). This pattern is recognized by the RAE as a regular conjugation pattern.