El gato duerme bajo la mesa.

Duerme is the third-person singular (él/ella/usted) form of the verb dormir in the present indicative. It literally means “he/she/it sleeps” or “is sleeping.” In Spanish, dormir is an o→ue stem-changing verb, so the o in the stem changes to ue in all present-tense forms except for nosotros and vosotros.

Spanish often uses the simple present to describe ongoing actions, habitual actions, and general truths.

• El gato duerme bajo la mesa can mean “The cat sleeps (or is sleeping) under the table.”
• If you want to emphasize “right now” you can use the present-progressive: El gato está durmiendo bajo la mesa.

Both are correct; the simple present is more succinct and very common in Spanish.

In Spanish every noun has a grammatical gender. Gato is a masculine noun, so it takes the masculine singular definite article el (“the”). If it were a feminine noun (like gata, the female cat), you would say la gata.

Spanish usually requires the definite article before countable nouns when you’re referring to a specific object.

• La mesa = “the table” (a particular table you and the speaker both know).
• If it were any table, you could say una mesa (“a table”) and have El gato duerme bajo una mesa.

Bajo is a preposition meaning “under” or “beneath.” In this sentence, it introduces the prepositional phrase bajo la mesa, indicating location.

Note: bajo can also be an adjective meaning “low,” but here it’s definitely a preposition.

Both mean “under the table,” but:

• bajo la mesa is more formal or literary.
• debajo de la mesa is the everyday, colloquial way most speakers use.

You can use either, but debajo de is far more common in spoken Latin American Spanish.

Yes. Spanish has flexible word order for emphasis or style.

• El gato duerme bajo la mesa is neutral, subject–verb–complement.
• Bajo la mesa duerme el gato puts focus on the location (“Under the table is where the cat sleeps”).

Both are grammatically correct.

None of these words carry a written accent because they follow Spanish stress rules:

• Words ending in a vowel, n, or s are stressed on the penultimate syllable by default.
• duer-me (ˈdwer-me), ba-jo (ˈba-xo), me-sa (ˈme-sa).

No accent marks are needed since the natural stress falls where it should.