La motxilla és a sota del llit.

Because motxilla is a feminine singular noun in Catalan, so it takes the feminine singular article la.

• la motxilla = the backpack
• el llit = the bed

As in many languages, grammatical gender is just part of the noun’s grammar. It does not mean the object is literally female.

Motxilla usually means backpack, rucksack, or sometimes school bag, depending on context.

In this sentence, the natural translation is simply the backpack.

És is the he/she/it is form of ser.

In Catalan, ser is very commonly used in neutral sentences that say where something is. So La motxilla és a sota del llit is a normal, natural way to say this.

You may also hear estar in some contexts or varieties, but for a straightforward location sentence like this, és is a very standard choice.

Here, a sota de is a common expression meaning under or below.

So:

• a sota del llit = under the bed

It is best to learn a sota de as a single location phrase.

Because the usual expression is a sota de.

English just says under, but Catalan often uses this longer phrase to express the same idea. So you should think of it as one unit:

• a sota de la taula = under the table
• a sota del llit = under the bed

Because de + el contracts to del in Catalan.

So:

• de + el llit -> del llit

This is a very common contraction. In the sentence, a sota de + el llit becomes a sota del llit.

Yes. Sota el llit is also correct and means under the bed.

Very roughly:

• sota el llit = a shorter, more direct form
• a sota del llit = a very common everyday expression

Both are natural, but the sentence you were given uses a sota de.

Because llit is a masculine noun in Catalan.

So:

• el llit = the bed
• after de, it becomes del llit

This is why the sentence has la motxilla but del llit.

The accent shows that és is the verb form meaning is.

It also helps distinguish it from es, which can be a different word in Catalan, often a pronoun. So the accent is important for both spelling and meaning.

Yes. The structure is very similar:

• La motxilla = the backpack
• és = is
• a sota del llit = under the bed

So the sentence follows subject + verb + location, which is the same basic order as English.

Normally, no. In a full sentence like this, you would usually keep the article: La motxilla.

Leaving it out would sound incomplete or unnatural in standard Catalan. If you mean the backpack, you need la.

Because baix usually means low or down, not the normal preposition under in this kind of sentence.

To say under the bed, Catalan normally uses:

• sota el llit
• a sota del llit

So for this sentence, a sota del llit is the natural choice.