In short

Mesoclisis is the one place in European Portuguese where an object pronoun goes inside the verb, not before it or after it. It happens with exactly two tenses - the simple future and the conditional (Lesson 32) - and only when the sentence would otherwise call for enclisis (Lesson 30). Instead of gluing the clitic onto the end, Portuguese splits the verb open and drops the pronoun into the seam between the stem and its ending: darei + o becomes dá-lo-ei (“I will give it”), diria + lhe becomes dir-lhe-ia (“I would tell him”). It looks alarming, and it is firmly formal and written - nobody orders coffee this way - but you must be able to read it, and produce it when the register (a legal text, a formal letter, careful oratory) demands it. Everything you need is already in place: the future/conditional endings from Lesson 32, and the clitic forms and -lo/-la allomorphs from Lessons 29-31.

The rule

When mesoclisis fires - all three conditions

Mesoclisis is required only when all of the following are true:

1. the verb is in the futuro simples or the condicional;
2. the clause is affirmative and the verb is not preceded by a proclisis trigger;
3. so the clitic would otherwise be enclitic (attached to the end).

Under those conditions EP does not allow the clitic after the whole word (darei-o is impossible). It also does not allow it before the word, because nothing is pulling it there. The clitic is therefore lodged in the middle.

If any proclisis trigger from Lesson 30 is present - negation (não, nunca, nada), a preverbal adverb (já, também, só), a subordinating conjunction (que, quando, se), a relative or interrogative word - then the clitic simply goes before the whole future/conditional verb, and there is no mesoclisis at all:

• Dir-lhe-ei a verdade. -> Não lhe direi a verdade.
• Dá-lo-ei amanhã. -> Só o darei amanhã.

Proclisis always wins; mesoclisis is only the “default enclisis” case reshaped for these two tenses.

How to build it - three slots

Split the synthetic tense into its stem and its personal ending, and put the clitic between them:

[ future / conditional stem ] - [ clitic ] - [ personal ending ]

The personal endings are exactly those of Lesson 32:

• future: -ei, -ás, -á, -emos, -ão
• conditional: -ia, -ias, -ia, -íamos, -iam

So falar + lhe in the future, person by person: falar-lhe-ei, falar-lhe-ás, falar-lhe-á, falar-lhe-emos, falar-lhe-ão.

The -lo / -la allomorph applies inside the word

When the clitic is o, a, os, as, the same rule as Lesson 31 kicks in: the stem’s final -r drops and the clitic becomes -lo, -la, -los, -las. A written accent then lands on the now-stressed stem vowel of -ar and -er verbs (-á-, -ê-), while -ir verbs take no accent (the stressed -i- needs none):

• amar + o -> amá-lo-ei (“I will love it/him”)
• vender + a -> vendê-la-ei (“I will sell it”)
• partir + os -> parti-los-ei (“I will break them”)
• pôr + o -> pô-lo-ei (“I will put it”)

Before the consonant-initial clitics (me, te, lhe, se, nos, lhes) the -r stays: dar-te-ei, chamar-se-á.

Irregular future/conditional stems carry over

The three verbs with an irregular synthetic stem (Lesson 32) keep that stem in mesoclisis:

• fazer -> far-: fá-lo-á (“he will do it”), far-se-ia (“it would be done”)
• dizer -> dir-: dir-lhe-ei (“I will tell him”), dir-se-ia (“one would say”)
• trazer -> trar-: trar-mo-ão (“they will bring it to me”)

Combined clitics can go inside too

The fused clitics of Lesson 50 (mo, to, lho, no-lo) sit in the seam just like a single pronoun. Because these begin with a consonant, the stem’s -r stays:

• dizer + lho -> dir-lho-ei (“I will tell it to him”)
• dar + mo -> dar-mo-á (“he will give it to me”)

Forms & patterns

The full future paradigm of dar with the clitic o (“I will give it”, “you will give it”, …):

A mixed sample across verbs, clitics and both tenses:

Examples

The last two show the same verbs losing mesoclisis the instant não or the adverb só appears: the clitic jumps to the front (proclisis).

Common mistakes

• darei-te / dar-ei-te -> dar-te-ei - in the future and conditional the clitic goes inside the verb, between stem and ending, never tacked onto the whole form.
• comprarei-o -> comprá-lo-ei - future + o needs mesoclisis and the Lesson 31 allomorph: the -r drops, o becomes -lo, and the stem takes an accent.
• Não dir-lhe-ei nada. -> Não lhe direi nada. - any proclisis trigger (here não) cancels mesoclisis and pulls the clitic in front of the verb.
• fazer-se-á / dizer-lhe-ei -> far-se-á / dir-lhe-ei - use the irregular future stem (far-, dir-, trar-), not the plain infinitive.
• da-lo-ei -> dá-lo-ei - keep the written accent on the stressed stem (dá-, vê-, fá-); dropping it changes the stress.
• Reaching for mesoclisis in a present or past tense -> it exists only in the futuro simples and the condicional; a present-tense command or statement uses enclisis or proclisis as normal (Lesson 30).

Tips

• Test three boxes before you write it: (1) future or conditional? (2) affirmative with no preverbal trigger? (3) would the clitic otherwise be enclitic? Only all-yes gives mesoclisis.
• Build it mechanically in three slots - stem + clitic + ending - and remember the ending is the ordinary Lesson 32 ending (-ei/-ás/-á/-emos/-ão, -ia/-ias/-ia/-íamos/-iam).
• For o/a/os/as, run the Lesson 31 allomorph inside the word: drop the -r, write -lo/-la, and accent the stem on -ar/-er verbs (amá-lo-ei, vendê-la-ei); -ir verbs take no accent (parti-lo-ei).
• The moment a não, a preverbal adverb, or a subordinating word turns up, forget mesoclisis and just say não lho direi, quando lho disser.
• Register reality: mesoclisis is formal, written EP. In speech people avoid it: EP reaches for the near future (vou dar-te, Lesson 11), while Brazilian Portuguese, in speech and writing alike, puts the clitic in front (te darei, vou te dar). Read it fluently; produce it only when the tone calls for it.