How do you form an adverb from an adjective in Spanish?

Take the feminine singular form of the adjective and add -mente. Rapido becomes rapida, then rapidamente (quickly). Lento becomes lenta, then lentamente (slowly). Adjectives that do not change for gender just take the suffix straight: feliz gives felizmente, facil gives facilmente. The feminine base is the only fiddly part - if you start from the masculine you get the wrong stem.

Does the adjective keep its accent when you add -mente?

Yes. The written accent on the adjective is retained even though -mente shifts the spoken stress: rapida keeps its accent in rapidamente, facil keeps its in facilmente, comun in comunmente. This is the one place in Spanish where a word carries two stresses, and the accent mark is the trace of the original adjective. Dropping it is a common written error.

What does Spanish use instead of -mente?

Spanish often prefers con plus an abstract noun where English would reach for an -ly adverb. Con cuidado (carefully) is more natural than cuidadosamente; con frecuencia (frequently) beats frecuentemente in speech; con paciencia, con cariño, con facilidad all do the work of an adverb. -mente adverbs can sound heavy when stacked, so native speakers thin them out this way.

Spanish Adverbs in -mente

English builds adverbs of manner with -ly: quick becomes quickly. Spanish does the same job with -mente, and the rule is almost mechanical. The trick is knowing what to attach it to, what to do with the accent, and when a native speaker would not use it at all.

The basic rule: feminine adjective + mente

Take the feminine singular of the adjective and add -mente.

rápido -> rápida -> rápidamente (quickly)
lento -> lenta -> lentamente (slowly)
claro -> clara -> claramente (clearly)
tranquilo -> tranquila -> tranquilamente (calmly)

If the adjective has no separate feminine form - that is, if it ends in -e or a consonant and stays the same for both genders - you just bolt -mente straight on.

feliz -> felizmente (happily)
fácil -> fácilmente (easily)
frecuente -> frecuentemente (frequently)
general -> generalmente (generally)

The single most common mistake is starting from the masculine. Rapidomente does not exist; it is rápidamente, from the feminine rápida.

The accent-retention rule

This is the detail that catches people out in writing. The adjective keeps its original written accent when -mente is added, even though the spoken stress now falls on the -men- syllable.

rápida -> rápidamente (the accent on the á stays)
fácil -> fácilmente
común -> comúnmente
práctica -> prácticamente

A -mente adverb is effectively the only Spanish word that carries two stresses: the original one marked by the accent, and the suffix stress on -men-. If the base adjective had no accent, the adverb has none either: lentamente, claramente, felizmente. So the rule is simple - copy the adjective's accent exactly, then add the suffix.

Table of common -mente adverbs

Adjective (masc.)	Feminine	Adverb	English
rápido	rápida	rápidamente	quickly
lento	lenta	lentamente	slowly
claro	clara	claramente	clearly
tranquilo	tranquila	tranquilamente	calmly
perfecto	perfecta	perfectamente	perfectly
fácil	(no change)	fácilmente	easily
feliz	(no change)	felizmente	happily
frecuente	(no change)	frecuentemente	frequently
general	(no change)	generalmente	generally
normal	(no change)	normalmente	normally

When Spanish prefers con + noun

Here is the thing the rulebooks skate over: native speakers do not actually use -mente as freely as English uses -ly. The suffix is long and heavy, and a sentence with two or three of them sounds clumsy. The usual escape route is con ("with") plus an abstract noun.

con cuidado = carefully (more natural than cuidadosamente)
con frecuencia = frequently (preferred over frecuentemente in speech)
con paciencia = patiently
con facilidad = easily (alongside fácilmente)
con cariño = affectionately

So habla con cuidado ("speak carefully") is more idiomatic than habla cuidadosamente. When you find yourself reaching for a long -mente adverb, ask whether con plus a noun would sound lighter. It usually does.

A few manner ideas have their own dedicated adverbs and never take -mente at all: bien (well), mal (badly), despacio (slowly), deprisa (quickly). Use these rather than inventing buenamente or malamente - those exist but mean something else entirely.

Dropping -mente on coordinated adverbs

When two -mente adverbs are joined by y, o or pero, Spanish drops the suffix from the first one and leaves only the feminine adjective. The -mente on the last adverb does the work for both.

Habló lenta y claramente. (He spoke slowly and clearly.) - not lentamente y claramente
Trabaja rápida pero cuidadosamente. (She works quickly but carefully.)
Lo explicó simple y directamente. (He explained it simply and directly.)

The dropped form is still the feminine adjective (lenta, rápida, simple), because that is the stem -mente would have attached to. This is not optional in careful writing - keeping -mente on both reads as redundant.

Common mistakes English speakers make

Building from the masculine. It is rápidamente, from rápida, never rápidomente. Always take the feminine base first.

Dropping the accent. Rapidamente without the accent is a spelling error. The adjective's accent survives the suffix: rápidamente, fácilmente, comúnmente.

Overusing -mente. Stacking three -mente adverbs in a sentence sounds heavy and non-native. Reach for con plus a noun, or a one-word adverb like bien or despacio, to break the rhythm.

Keeping -mente on both coordinated adverbs. Lentamente y claramente should be lenta y claramente. Only the last adverb in the pair carries the suffix.