Adjectives acting as adverbs
In English, we usually add "-ly" to an adjective to turn it into an adverb describing how an action is done (e.g., clear becomes clearly). While Spanish has a similar ending (-mente), it is very common to simply use the adjective itself.
When an adjective acts as an adverb, it becomes invariable. It is locked into its singular, masculine form, regardless of the gender or number of the subject performing the action.
| The moderator spoke clearly from the podium because he was very eloquent. | El moderador habló claro desde el atril porque era muy elocuente. |
Even though the subject in the next example is a woman (la mujer), the adverb describing how she spoke remains masculine (directo). It does not change to directa because it modifies the verb (habló), not the speaker.
| The eloquent woman went to the podium and spoke directly to the audience. | La mujer elocuente fue al atril y habló directo al público. |
Critiquing a speech
Use these invariable adjectives to critique public speaking—describing how someone speaks, breathes, or projects their voice. Common adjectives used adverbially include claro (clearly), fuerte (strongly/loudly), lento (slowly), rápido (fast/quickly), and profundo (deeply).
| To be persuasive, you have to speak slowly and improve your intonation. | Para ser persuasivo, tienes que hablar lento y mejorar tu entonación. |
| Due to nervousness, the candidate hesitated and did not project his voice strongly. | Por el nerviosismo, el candidato titubeó y no proyectó fuerte la voz. |
| At the podium, the boy breathed deeply to improve the tone. | En el atril, el chico respiró profundo para mejorar el tono. |
| The moderator thought that the eloquent actor had spoken slowly and confidently. | El moderador pensaba que el actor elocuente había hablado lento y seguro. |