Hallamos la llave bajo la mesa.

Yes. Hallamos is grammatically ambiguous.

It can be:

• present indicative: we find
• preterite: we found

That happens because with regular -ar verbs, the nosotros form looks the same in those two tenses:

• hallamos = present
• hallamos = preterite

So in real Spanish, context tells you which meaning is intended. In isolation, both are possible.

Both verbs can mean to find.

The difference is mainly one of style and frequency:

• encontrar is more common in everyday speech
• hallar is perfectly correct, but it can sound a bit more formal, literary, or written

In Spain, people will understand hallar easily, but in casual conversation, encontrar is often the more usual choice.

Because Spanish usually drops subject pronouns when the verb ending already shows who is doing the action.

Here, hallamos already tells you the subject is we. So nosotros is unnecessary unless you want to add:

• emphasis
• contrast
• clarity

For example:

• Hallamos la llave = normal, neutral
• Nosotros hallamos la llave = we found the key, maybe not someone else

Because llave is a feminine singular noun, so it takes the feminine singular definite article la.

Agreement in Spanish works like this:

• el for masculine singular nouns
• la for feminine singular nouns

So:

• la llave
• not el llave

You normally just have to learn the noun together with its gender.

Because mesa is also a feminine singular noun, and here it refers to a specific table.

Spanish normally uses the article in this kind of phrase:

• bajo la mesa = under the table

You would not normally say bajo mesa in standard Spanish.

So both nouns take the article they need:

• la llave
• la mesa

Here bajo is a preposition meaning under or beneath.

So:

• bajo la mesa = under the table

A very common alternative is:

• debajo de la mesa

Both are correct. The difference is mostly stylistic:

• bajo is a bit more compact and can sound slightly more formal or written
• debajo de is very common in everyday speech and may feel a little more explicit

So this sentence could also be:

• Hallamos la llave debajo de la mesa

Yes. Spanish word order is flexible, although the original order is the most neutral here.

Neutral:

• Hallamos la llave bajo la mesa

Possible alternative:

• Bajo la mesa hallamos la llave

That second version puts more emphasis on where the key was found. It is grammatical, but less neutral.

So the original sentence is the straightforward, unmarked way to say it.

A few useful points:

• The h in Spanish is silent

  • hallamos begins with the sound a..., not an English h

• In most of Spain, ll is pronounced like the y sound in English yes

  • hallamos ≈ a-YA-mos
  • llave ≈ YA-be or YA-ve

• The v and b sounds are not strongly distinguished in standard Spanish pronunciation, so llave does not sound like English v in a strong way

So the two trickiest things for English speakers are:

1. don’t pronounce the h
2. pronounce ll like a Spanish y sound in most modern varieties of Spain

In this sentence, the natural interpretation is that it describes the location of the key: the key was under the table.

So the idea is:

• we found the key
• the key was under the table

In practice, that is also the place where we found it, so the two ideas overlap. But the phrase most naturally tells you the key’s location, not our location. It does not mean that we were under the table when we found it.