Learn Hardcore Spanish (Latin America): Cuando estudio mentalmente una lista de palabras sin mirarla, mi memoria visual y auditiva trabajan juntas. - When I mentally study a list of words without looking at it, my visual and auditory memory work together.

Cuando estudio… (present indicative) = Whenever I study… / When I study (in general).
This is used for habits or general truths. Your sentence describes what usually happens when you do this kind of mental study, so the simple present is correct.
Cuando estoy estudiando… would emphasize an action in progress right now (“when I am in the middle of studying…”). It’s possible, but it sounds more focused on a specific ongoing situation, not a general habit.
Cuando estudie… (present subjunctive) is used when the main clause is about the future or something not yet realized:
- Cuando estudie mañana, me tomaré un café. = When I study tomorrow, I’ll have a coffee.

In your sentence, you’re talking about what normally happens, not a future one-time event, so indicative present: “Cuando estudio…” is the natural choice.

Why does “mentalmente” come after “estudio”? Could it go in another position?

Mentalmente is an adverb (“mentally”), and Spanish adverbs are fairly flexible in position, but they have preferred spots:

Cuando estudio mentalmente una lista de palabras… (original)
Cuando mentalmente estudio una lista de palabras… (less common, more marked)
Cuando estudio una lista de palabras mentalmente… (also fine)

The most neutral and natural is like the original: verb + adverb + object.

Saying “mentalmente estudio…” is grammatically correct, but it sounds slightly more formal or stylized, like you’re emphasizing the manner more than usual.

You could also say:

Cuando repaso mentalmente una lista de palabras…

Here repaso = “I review,” which is often more idiomatic than estudio in a memorization context, but estudio mentalmente is fully correct.

Why is it “una lista de palabras” and not “un lista de palabras”?

The article una/un agrees in gender and number with the noun it modifies:

la lista → una lista (feminine singular)
el libro → un libro (masculine singular)

Here the head noun is lista (feminine), and de palabras just describes what kind of list it is (“of words”), so:

una lista de palabras = a list of words

You cannot let palabras (feminine plural) control the article; it always agrees with the main noun (lista), not the noun in the de phrase.

Why is it “sin mirarla” and not something like “sin miro la lista”?

In Spanish, after a preposition (like sin, para, por, de, a, en), you must use the infinitive form of the verb, not a conjugated form:

❌ sin miro
✅ sin mirar = without looking

So the basic structure is:

sin + infinitive → sin mirar (without looking)

Then you add the direct object pronoun la (“it/her”) to represent la lista (“the list”):

sin mirarla = without looking at it (i.e., the list)

What does the “la” in “mirarla” refer to, and why is it attached to the verb?

La is a direct object pronoun meaning “it” (for feminine singular nouns) or “her”. In this sentence it clearly refers back to:

una lista → la (because lista is feminine singular)

So:

mirar la lista = to look at the list
mirarla = to look at it

Spanish allows (and prefers, in this case) attaching object pronouns to the end of an infinitive:

sin mirar la lista
sin mirarla

Both mean the same, but sin mirarla is shorter and very natural in speech and writing.

Could you also say “sin la mirar” instead of “sin mirarla”?

Sin la mirar is grammatically possible but much less common and more emphatic. Native speakers overwhelmingly prefer:

sin mirarla

General rule with infinitives + pronouns:

You can put the pronoun before the verb:
- la mirar
Or attach it to the infinitive:
- mirarla

Both are allowed, but with infinitives, the attached form is far more usual and sounds more natural, especially after a preposition like sin:

✅ sin mirarla (most natural)
⚠️ sin la mirar (unusual, sounds marked or literary)

Why is there no subject pronoun “yo” in “Cuando estudio…”?

Spanish is a “pro-drop” language: subject pronouns are often omitted because the verb ending already tells you who the subject is.

estudio → clearly 1st person singular (“I study”)
So yo is not needed.

You can add yo for emphasis or contrast:

Cuando yo estudio mentalmente…
(e.g., to contrast with how others study)

But in neutral statements like yours, omitting yo is more natural.

Why is the verb “trabajan” plural instead of singular “trabaja”?

The subject is really two things working together:

mi memoria visual
(mi memoria) auditiva

So logically, you have two “memories” (visual and auditory) = plural subject → trabajan.

The sentence compresses this by saying “mi memoria visual y auditiva” instead of repeating memoria:

Full version: mi memoria visual y mi memoria auditiva trabajan juntas
Shortened version (yours): mi memoria visual y auditiva trabajan juntas

Verb agreement in Spanish can follow meaning, not just strict form. Since we clearly mean two types of memory, the plural trabajan is very natural.

Would “trabaja” be possible?
Yes, some speakers might say:

…mi memoria visual y auditiva trabaja…

focusing on “my memory” as a single system with two aspects. But given the plural adjective “juntas”, the plural trabajan is the best match.

Why is it “juntas” and not “juntos” or “junto”?

Juntas is an adjective meaning “together,” and it must agree in gender and number with what it refers to.

Hidden subject: mis memorias visual y auditiva (two feminine nouns: memoria and memoria) → feminine plural.

So we need:

juntas (feminine plural)

If the subject were masculine plural:

mis sentidos visual y auditivo trabajan juntos (my visual and auditory senses work together) → juntos

If it were a single feminine thing:

mi memoria visual y auditiva trabaja junta (treating it as one memory system) → junta

In your version, we treat them as two feminine things working together, so juntas is correct.

How does “mi memoria visual y auditiva” work grammatically? Is “memoria” singular or plural here?

Formally, memoria appears only once, so grammatically it’s singular:

mi memoria visual y auditiva
= my visual and auditory memory

This structure is common: one noun + two adjectives:

mi casa grande y luminosa = my big, bright house
un problema político y social = a political and social problem

But in your sentence, agreement (trabajan, juntas) shows the speaker is thinking in terms of two kinds of memory:

visual memory
auditory memory

So grammatically, memoria is singular, but semantically we treat it as two memories joined. That’s why the verb and juntas go to plural.

Why is “mirar” used instead of “ver”?

English often uses “see” where Spanish prefers “mirar” (“to look at”):

ver = to see (perceive with your eyes, often more passive)
mirar = to look at (active, intentional)

In this sentence, you mean “without looking (at the list)”, which is an intentional action, so mirar is more precise:

sin mirarla = without looking at it (the list)

If you said sin verla, it would still be understood, but it shifts slightly more to “without seeing it”, which is not exactly what you mean in a memory practice context.

Why is there a comma before “mi memoria visual y auditiva trabajan juntas”?

The sentence has two clauses:

Cuando estudio mentalmente una lista de palabras sin mirarla,
→ time clause: When(ever) I mentally study a list of words without looking at it…
mi memoria visual y auditiva trabajan juntas.
→ main clause: …my visual and auditory memory work together.

In Spanish:

When a subordinate clause (like one starting with cuando) comes before the main clause, it is normally followed by a comma.
When it comes after, the comma is usually omitted:
- Mi memoria visual y auditiva trabajan juntas cuando estudio mentalmente una lista de palabras sin mirarla.

So the comma here is standard punctuation separating the initial “cuando” clause from the main statement.