Learn Hardcore Spanish (Latin America): Mi perro gordito duerme en el sofá cómodo. - My chubby dog sleeps on the comfortable sofa.

gordo = fat, chubby (can sound neutral or a bit blunt depending on tone/context)
gordito = diminutive of gordo, often more affectionate: chubby, a bit fat, my chunky little…

In the sentence, mi perro gordito suggests affection, like my chubby little dog or my chubby dog said lovingly, not insultingly. Diminutives in Spanish are very commonly used to soften or show affection: gordito, perrito, casita, abuelita, etc.

Why is the adjective after the noun in perro gordito instead of before, like in English?

In Spanish, the default position of descriptive adjectives is after the noun:

perro gordito = chubby dog
sofá cómodo = comfortable sofa

So: noun + adjective is the normal pattern.
Adjective + noun also exists in Spanish but usually adds emphasis, subjectivity, or poetic style (and some specific adjectives are more common before the noun). For a basic descriptive sentence like this, perro gordito is the natural word order.

Is gordito agreeing with perro in gender and number? How would it change?

Yes. Adjectives in Spanish must agree with the noun in gender (masculine/feminine) and number (singular/plural):

Masculine singular: perro gordito
Feminine singular: perra gordita
Masculine plural: perros gorditos
Feminine plural: perras gorditas

Here, perro is masculine singular, so gordito is also masculine singular.

Why is it duerme and not dormir or something like dorma?

The verb is dormir (to sleep). In this sentence we need he/she/it sleeps → present indicative, 3rd person singular.

Dormir is irregular:

yo duermo
tú duermes
él / ella / usted duerme
nosotros dormimos
ustedes / ellos duermen

Since the subject is mi perro (third person singular), the correct form is duerme.

dormir is the infinitive (to sleep)
dorma would be a subjunctive form, not used here.

Why is there no subject pronoun like él in front of duerme?

Spanish usually omits subject pronouns because the verb ending already tells you who the subject is:

(Él) duerme. = He sleeps.
(Ella) duerme. = She sleeps.
(Mi perro) duerme. = My dog sleeps.

In this sentence, we already have a clear subject mi perro gordito, so there is no need for él. Adding él would sound wrong because él and mi perro would compete as two different subjects.

Why is en used here if in English we say "on the sofa," not "in the sofa"?

Spanish en can mean in, on, or at depending on context. Here it corresponds to on:

duerme en el sofá = sleeps on the sofa
vive en México = lives in Mexico
está en casa = is at home

You could also say sobre el sofá (more literally on top of the sofa), but en el sofá is the most common everyday way to say on the sofa.

Why is it el sofá cómodo and not un sofá cómodo?

el = the (definite article)
un = a / an (indefinite article)

el sofá cómodo implies a specific sofa, probably one both speaker and listener already know (the sofa at home, the usual one).

If you said:

Mi perro gordito duerme en un sofá cómodo.

it would mean on a comfortable sofa (some sofa, not specified which one). The original sentence assumes the sofa is known or uniquely identifiable, so el is used.

Why does sofá have an accent mark?

Spanish has stress rules:

Words ending in vowel, -n, or -s are normally stressed on the second-to-last syllable.
Words ending in other consonants are normally stressed on the last syllable.

sofá ends in a vowel (a), so by default it would be stressed on the second-to-last syllable: SO-fa. But we actually pronounce it so-FÁ (stress on the last syllable). To show this exception, it needs a written accent: sofá.

So the accent mark tells you to stress the last syllable: so-FÁ.

Why is it sofá cómodo and not sofá cómoda?

sofá is a masculine noun in Spanish, despite ending in -a. Some masculine nouns do end in -a (e.g., el día, el mapa, el problema, el sofá).

Adjectives must agree with the grammatical gender of the noun:

Masculine: sofá cómodo
Feminine: would be sofá cómoda, but that would be incorrect because sofá is not feminine.

If the noun were feminine, for example la silla (the chair), you’d say:

la silla cómoda = the comfortable chair

Could I say mi gordito perro instead of mi perro gordito?

Grammatically, mi gordito perro is not wrong, but it sounds unnatural in everyday Spanish. The normal, neutral order is:

mi perro gordito

When you put the adjective before the noun (mi gordito perro), it sounds more literary, poetic, or stylistically marked, and would usually require a special context to feel right. For regular speech and writing, stick with noun + adjective here.

Is there any difference between sofá cómodo and cómodo sofá?

Yes, mostly in tone and emphasis:

el sofá cómodo = the comfortable sofa (neutral, descriptive; most common)
el cómodo sofá = the comfortable sofa, but with a bit more emphasis or a stylistic/poetic feel, like you’re highlighting its comfort in a more subjective way.

In normal conversation, el sofá cómodo is the standard. el cómodo sofá is possible but sounds more literary or emphatic.

Could I say Mi perrito gordito duerme en el sofá cómodo? How does that change the meaning?

Yes, that’s perfectly correct:

perrito is the diminutive of perro → little dog / doggie
gordito is the diminutive of gordo → chubby / a little fat in an affectionate way

Mi perrito gordito would sound even more affectionate and cute than mi perro gordito, like saying my chubby little doggie. It intensifies the sense that the speaker is fond of the dog.