Learn Hardcore Spanish (Latin America): Últimamente estoy cansado cuando estudio en la noche.

Estar is used for states/conditions that can change, especially physical or emotional states:
- Estoy cansado. = I’m (feeling) tired.
- Estoy enfermo. = I’m (currently) sick.
Ser is used for inherent characteristics, identity, and more permanent traits:
- Soy alto. = I’m tall.
- Soy mexicano. = I’m Mexican.

If you said soy cansado, it would sound like “I am a tiring person” or “I tend to be a weary type,” an odd personality description. To say “I’m tired” (as in, right now / these days), you need estoy cansado.

Why is it cansado and not cansada? How does the adjective change?

Adjectives in Spanish must agree in gender and number with the noun they describe. Here the noun is the implied subject yo.

A man (or boy) would say: Estoy cansado.
A woman (or girl) would say: Estoy cansada.

If you were talking about more than one person:

Group of only males (or mixed group): Estamos cansados.
Group of only females: Estamos cansadas.

So cansado in the sentence assumes the speaker is male. A female speaker would say: Últimamente estoy cansada cuando estudio en la noche.

Why is there no yo in estoy cansado? When can the subject pronoun be omitted?

Spanish is a “pro-drop” language: you normally omit subject pronouns when the verb form already makes the subject clear.

Estoy can only mean “I am”, so yo is not needed:
- (Yo) estoy cansado.

You usually add yo only for emphasis or contrast:

Yo estoy cansado, pero ella no.
(I am tired, but she isn’t.)

In everyday speech and writing, omitting yo here is the most natural choice.

What exactly does últimamente mean, and where can it go in the sentence?

Últimamente means “lately / recently / in recent times.” It’s formed from último (last) + -mente (like English -ly).

In terms of position, it’s flexible:

Últimamente estoy cansado cuando estudio en la noche.
Estoy cansado últimamente cuando estudio en la noche.
Estoy cansado cuando estudio en la noche últimamente. (possible, but sounds a bit odd; usually you’d place it earlier)

The most natural options are usually:

At the beginning: Últimamente estoy cansado…
Just before or after the main verb phrase: Estoy últimamente muy cansado… / Estoy muy cansado últimamente.

All keep the same basic meaning: “Lately I’ve been tired when I study at night.”

Why does últimamente have an accent on the ú?

Últimamente is an esdrújula word: the stress falls on the third syllable from the end.

Ul-ti-ma-men-te → the stressed syllable is úl (the 3rd from the end).

In Spanish, all esdrújula words carry a written accent, so últimamente must have the accent on the ú. This is a regular spelling rule, not an exception.

Do we need a comma after Últimamente?

No comma is required here.

Spanish typically does not separate a short initial adverbial like Últimamente with a comma when it simply sets the time frame:

Últimamente estoy cansado cuando estudio en la noche. ✔

You can sometimes see a comma added for extra pause or emphasis — “Últimamente, estoy cansado…” — but standard style guides prefer no comma in a simple sentence like this.

Why is it cuando estudio and not cuando estoy estudiando or cuando estudie?

Three things are going on here:

Simple present vs. present progressive
- English: when I study / when I’m studying
- Spanish very often uses the simple present for general or habitual actions, where English might use either form:
  - Cuando estudio en la noche, estoy cansado.
    = When I (usually) study at night, I’m tired.
Cuando estoy estudiando is possible, but it sounds more like a specific ongoing situation (“when I happen to be in the middle of studying right then”), rather than a general habit.
Indicative vs. subjunctive with cuando
- Cuando uses the indicative (cuando estudio) for habitual or generally true actions.
- It uses the subjunctive (cuando estudie) when referring to a future or uncertain action:
  - Cuando estudie esta noche, voy a estar cansado.
    = When I (eventually) study tonight, I’m going to be tired.
In your sentence, the meaning is habitual (“these days, whenever I study at night, I’m tired”), so cuando estudio (present indicative) is the natural choice.

Why is it en la noche and not por la noche or at night directly?

The literal phrase is en la noche = “in the night,” but in English we say “at night.” It’s just a difference in prepositions between the two languages.

Common options in Spanish are:

En la noche – widely used in Latin America for “at night” in many contexts.
Por la noche – very common too (especially in Spain), also “at night / in the evenings.”
De noche – “at night / by night” in a more general sense (at nighttime, not during the day).

All can be correct depending on region and nuance:

Últimamente estudio en la noche.
Últimamente estudio por la noche.
Últimamente estudio de noche.

In Latin America, en la noche is very natural. Using “en la noches” (with an s) would be incorrect; the fixed phrase is en la noche.

Could I say Últimamente me canso cuando estudio en la noche instead? What’s the difference from estoy cansado?

Yes, Últimamente me canso cuando estudio en la noche is correct and natural. The nuance is slightly different:

Estoy cansado cuando estudio en la noche.
- Focus on the state: “I am (in a tired state) when I study at night.”
Me canso cuando estudio en la noche.
- Focus on the process: “I (get tired / become tired) when I study at night.”

With me canso, you’re emphasizing that studying at night makes you tired (the action causes the fatigue). With estoy cansado, you’re describing how you find yourself (your condition) when you study at night. In many contexts they’re almost interchangeable.

Can I change the word order, like Cuando estudio en la noche, últimamente estoy cansado?

You can change the word order quite freely in Spanish to adjust emphasis without changing the basic meaning. All of these are grammatical:

Últimamente estoy cansado cuando estudio en la noche.
(Neutral; “Lately I’m tired when I study at night.”)
Cuando estudio en la noche, últimamente estoy cansado.
(Slight extra emphasis on the when: “When I study at night, lately I’m tired.”)
Estoy cansado cuando estudio en la noche últimamente.
(Grammatically OK, but sounds less smooth; últimamente is usually better placed earlier.)

Spanish allows this flexibility as long as the sentence remains clear and the verb–subject agreement is respected.