Learn Hardcore Spanish (Latin America): Compro una docena de huevos y media docena de limones. - I buy a dozen eggs and half a dozen lemons.

Compro already tells us it’s I who is buying.
You only add yo for emphasis or contrast:
- Yo compro una docena de huevos, pero él compra dos.
  I buy a dozen eggs, but he buys two.

So Compro una docena de huevos… is perfectly normal and actually more natural in everyday Spanish than Yo compro… in this context.

Why is it Compro and not Estoy comprando if the meaning is “I’m buying”?

Spanish present tense (compro) is more flexible than English:

Compro una docena de huevos can mean:
- “I buy a dozen eggs” (habitually), or
- “I’m buying a dozen eggs” (right now / in this situation).

If you really want to emphasize that it’s happening right now, you can use the progressive:

Estoy comprando una docena de huevos.

In many everyday contexts, especially in narration or when describing what you usually do at a store, compro alone is enough and very natural.

Why is it una docena and not just docena?

In Spanish, docena is a regular noun meaning a set of twelve, not a bare number. As a countable noun, it normally needs an article:

una docena de huevos – a dozen eggs
tres docenas de huevos – three dozen eggs

Leaving out the article (docena de huevos) sounds incomplete in this sentence. (You might see docena without article in some fixed expressions or headlines, but in normal speech you say una docena.)

Why is it media docena and not medio docena?

Docena is a feminine noun (la docena), so any adjective that agrees with it must also be feminine:

media docena – half a dozen (feminine)
medio kilo – half a kilo (masculine, because kilo is masculine: el kilo)

So:

✅ media docena de limones
❌ medio docena de limones

Could I say una media docena de limones instead of media docena de limones?

Yes, una media docena de limones is also correct and quite common. Both forms are used:

media docena de limones
una media docena de limones

The meaning is the same: “half a dozen lemons.”
In many contexts, speakers drop the una, but including it is not wrong.

Why do we say media docena de limones and not something like mitad docena de limones?

Spanish uses medio / media directly before a noun to mean half (a):

media docena, medio kilo, media hora.

Mitad is another word for half, but it works differently in grammar. It appears as la mitad de + noun:

la mitad de la docena – half of the dozen
la mitad de los limones – half of the lemons

So for “half a dozen lemons” you say:

media docena de limones (or una media docena de limones),
not mitad docena de limones.

Why is there a de in una docena de huevos and media docena de limones?

When a noun of quantity is followed by what you are counting, Spanish uses de:

una docena de huevos – a dozen of eggs
un kilo de manzanas – a kilo of apples
un vaso de agua – a glass of water

So docena de huevos / docena de limones is the standard pattern:
[quantity noun] + de + [what is being counted].

Why are huevos and limones plural after una docena and media docena?

Because in Spanish (as in English) you’re talking about several individual items:

“a dozen eggs” → una docena de huevos (12 separate eggs)
“half a dozen lemons” → media docena de limones (6 separate lemons)

Using the singular (una docena de huevo, media docena de limón) would sound wrong unless huevo/limón were being used in some special, non-countable sense (which they aren’t here).

Why does limón lose the accent in limones?

Limón has an accent because:

It’s stressed on the last syllable: li–MÓN
Words ending in n, s, or vowel are normally stressed on the second-to-last syllable, so a stress on the last syllable needs a written accent: limón.

In the plural limones:

It’s stressed on the second-to-last syllable: li–MO–nes.
This matches the regular rule (no special stress), so the written accent is not needed.

So: limón (singular, with accent) → limones (plural, no accent).

Could I say Compro una docena de huevos y media de limones, without repeating docena?

Yes, in real speech many people would say:

Compro una docena de huevos y media de limones.

Here, media clearly refers to docena, which is understood and omitted. This kind of omission (ellipses) is common when the repeated noun would be obvious.

The full version (… y media docena de limones) is a bit more explicit and neutral; both are fine.

How would I say “I buy a dozen and a half eggs” (18 eggs), and how is that different from this sentence?

For one and a half dozen eggs (18 eggs), you’d typically say:

Compro una docena y media de huevos.

Notice the structure:

una docena y media de huevos = 1½ dozen eggs.

Your original sentence is:

Compro una docena de huevos y media docena de limones.

That means two separate things:

1 dozen eggs (12 eggs)
½ dozen lemons (6 lemons)

So una docena y media de huevos = 18 eggs, whereas the original is 12 eggs + 6 lemons.

In Latin America, does huevos ever sound rude or slangy?

Yes, in many Spanish-speaking countries huevos is also a colloquial word for testicles and appears in many slang expressions.

However:

In shops, markets, recipes, and normal everyday contexts, huevos is the standard, correct word for eggs, and no one finds it inappropriate.
The slang meaning usually becomes clear only from tone, context, or certain expressions (for example, some insults or idioms).

So Compro una docena de huevos is completely normal and polite in Latin America.

In Latin America, are limones always “lemons,” or can they be “limes” too?

Usage varies by country:

In much of Latin America, limón can refer to what English calls lime (the green one) and sometimes also to lemon (the yellow one), depending on the region.
Some places distinguish:
- limón or limón verde – lime
- limón amarillo – lemon
- lima – in some areas, a different kind of citrus.

In this sentence, media docena de limones just means “a half dozen of the local fruit they call limón,” which may be limes, lemons, or both, depending on the country.