Mi madre prefiere dejar el azucarero junto a las tazas del desayuno.

Because after preferir, Spanish normally uses the infinitive when the subject stays the same.

• Mi madre prefiere dejar... = My mother prefers to leave...

Here, prefiere is the conjugated verb, and dejar stays in the infinitive, just like prefers to leave in English.

Compare:

• Prefiero comer ahora. = I prefer to eat now.
• Ella prefiere esperar. = She prefers to wait.

If the subject changes, Spanish often uses que + subjunctive instead:

• Mi madre prefiere que yo lo deje ahí. = My mother prefers me to leave it there.

Prefiere is the third-person singular present tense of preferir.

It matches mi madre, which is she:

• yo prefiero
• tú prefieres
• él/ella prefiere
• nosotros preferimos
• vosotros preferís
• ellos prefieren

Also, preferir is a stem-changing verb: e → ie in most present-tense forms.

So:

• preferir → prefiere
• not preferer or prefera

Spanish usually uses a possessive adjective like mi, tu, su, etc. with family words when saying my mother, your brother, and so on.

So:

• mi madre = my mother
• mi padre = my father
• mi hermana = my sister

You would not normally say la mi madre in modern standard Spanish.

Spanish can also sometimes use the definite article with family members in other structures, but in a simple phrase like this, mi madre is the normal choice.

Here, dejar means to leave in the sense of to put / to keep / to leave something somewhere.

So in this sentence, it is not about leaving a place. It means something like:

• to leave the sugar bowl next to the breakfast cups
• to keep the sugar bowl beside the cups

Common meanings of dejar include:

• leave something somewhere
• let / allow
• stop / give up in some contexts

Examples:

• Deja las llaves en la mesa. = Leave the keys on the table.
• Me deja salir. = She lets me go out.

El azucarero means the sugar bowl or the sugar container.

It comes from azúcar = sugar.

So:

• azúcar = the substance, sugar
• azucarero = the container that holds sugar

The ending -ero often forms words for a container, place, or object related to something.

A few examples:

• sal = salt → salero = salt shaker
• azúcar = sugar → azucarero = sugar bowl / sugar container

Because the stress falls differently.

• azúcar is stressed on the first syllable: A-zú-car
• azucarero is stressed in the normal pattern for the word, so it does not need a written accent: a-zu-ca-RE-ro

Spanish accent marks are not random; they show either:

1. an unusual stress pattern, or
2. sometimes help distinguish words

So the accent in azúcar is part of normal spelling, but when the word changes to azucarero, the stress pattern changes and the accent mark disappears.

Junto a means next to, beside, or close to.

In this sentence:

• junto a las tazas = next to the cups

It is a very common expression for location.

Similar expressions:

• junto a = next to / beside
• al lado de = next to / at the side of
• cerca de = near

Examples:

• El libro está junto a la lámpara. = The book is next to the lamp.
• Se sentó junto a mí. = He/She sat next to me.

Because junto a is a fixed expression.

You should learn it as a chunk:

• junto a = next to

So Spanish does not say just junto las tazas here. It needs the preposition a:

• junto a las tazas

This is similar to how English requires certain prepositions in fixed expressions, even when they do not translate word for word.

Las tazas del desayuno literally means the cups of the breakfast, but in natural English we would usually say the breakfast cups or the cups for breakfast.

Here, del desayuno identifies which cups we mean: the ones associated with breakfast.

Why del?

Because:

• de + el = del

So:

• las tazas del desayuno = the cups of/for breakfast

Could tazas de desayuno exist? Sometimes Spanish uses de + noun in a more descriptive way, but in this sentence las tazas del desayuno sounds like a specific set of cups used at breakfast or the cups on the breakfast table.

Del is the contraction of de + el.

So:

• de el desayuno becomes del desayuno

This contraction is mandatory in normal Spanish, except when el is part of a proper name.

Examples:

• el libro del profesor = the teacher’s book
• la puerta del coche = the car door

But:

• de El Escorial does not contract, because El Escorial is a proper name

In your sentence, desayuno is a normal masculine noun, so de + el becomes del.

Because Spanish nouns have grammatical gender and number, and the article has to agree with them.

• azucarero is masculine singular → el azucarero
• tazas is feminine plural → las tazas

So the article changes to match the noun.

A quick breakdown:

• el = masculine singular
• la = feminine singular
• los = masculine plural
• las = feminine plural

Here it is a noun meaning breakfast.

It comes after del, so it is clearly part of a noun phrase:

• del desayuno = of the breakfast / for breakfast

But desayuno can also be a verb form:

• yo desayuno = I have breakfast

So the same word can be:

• noun: el desayuno = breakfast
• verb: desayuno = I have breakfast

In this sentence, it is definitely the noun.

Yes, Spanish word order is somewhat flexible, though the original sentence is perfectly natural.

Original:

• Mi madre prefiere dejar el azucarero junto a las tazas del desayuno.

You could also say:

• Mi madre prefiere dejar junto a las tazas del desayuno el azucarero.

That version is grammatical, but it sounds a bit more marked or stylistically different. The original order is more neutral and natural for most everyday contexts.

So for learners, the original version is the best one to use.

In most of Spain, z is pronounced like the th in think.

So:

• azucarero sounds roughly like a-thu-ca-RE-ro
• tazas sounds roughly like TA-thas

This is one of the main pronunciation features of Spain Spanish.

A learner should also notice:

• j in junto is a strong throaty sound
• r in madre is a tapped Spanish r
• z in Spain is not like English z

In much of Latin America, z would sound more like s, but since you are learning Spanish from Spain, the th-like pronunciation is the one to expect.