-no/-na

In Portuguese, when you place a direct object pronoun after a verb (a placement called enclisis), the pronoun's form may change depending on the verb's final sound.

If the verb ends in a nasal sound, the third-person direct object pronouns o, a, os, and as transform into -no, -na, -nos, and -nas. Note that -nos can be ambiguous, as it represents both the transformed 3rd person plural masculine pronoun ('them') and the 1st person plural pronoun ('us'). It is important to note that other pronouns like me, te, nos, vos, and lhe do not change their form (e.g., Eles dão-me). Unlike the rule for verbs ending in -r, -s, or -z, verbs ending in nasal sounds keep their original spelling. Because the verb's spelling doesn't change, you don't need to add any new written accent marks to maintain the original spoken stress (e.g., COM-pram remains COM-pram-no).

Common Nasal Endings:

• -m: Found in most 3rd person plural verbs (like compram or fazem) and some 3rd person singular verbs like tem.
• -ão: Found in verbs like dão.
• -õe / -õem: Found in the verb pôr and its derivatives (e.g., põe, põem, compõe, compõem).
• -êm / -eem: Found in the plural forms of ter (e.g., têm), as well as common verbs like veem (plural of ver) and leem (plural of ler).

Attractor Words (Palavras Atrativas):
Remember that certain words (like não, nunca, que, or já) act as "attractors" and force the pronoun to come before the verb (obligatory proclisis). When this happens, the -no/-na rule does not apply because the pronoun is no longer attached to the end of the verb. For example, Eles compram-no becomes Eles não o compram (not Eles não compram-no).

Future and Conditional Tenses:
Note that future and conditional verbs ending in nasal sounds (like comprarão) do not use -no/-na. Because these tenses require mesoclisis (splitting the verb), they revert to the -lo/-la rule. For example, comprarão + o becomes comprá-lo-ão, not comprarão-no.

Regional Differences:
In European Portuguese, this rule is strictly followed. In Brazilian Portuguese, this form is primarily used in formal writing. In casual Brazilian speech, people often use proclisis, omit the pronoun, or use subject pronouns as objects (e.g., Eu vi ele) to avoid this construction.