Mi madre dice que el pulpo con patata está delicioso.

Mi is the singular possessive adjective meaning my, and madre means mother. So mi madre = my mother.

A useful thing to remember is that Spanish usually does not use de here. You do not say something like la madre de mí for my mother.

Also, with family words, Spanish can use either:

• mi madre = my mother
• la madre = the mother / my mother, if the context already makes it clear whose mother you mean

In this sentence, mi madre is the most direct and natural choice.

Because the subject is mi madre, which is she.

The verb is decir = to say / to tell.
In the present tense:

• yo digo = I say
• tú dices = you say
• él/ella dice = he/she says

So:

• Mi madre dice = My mother says

Here, que means that and introduces the clause that follows:

• Mi madre dice que... = My mother says that...

In English, that is often optional:

• My mother says the octopus...
• My mother says that the octopus...

In Spanish, que is normally kept. Leaving it out would sound wrong here.

Spanish uses articles more often than English does.
So el pulpo literally means the octopus, but in context it can refer to:

• a specific octopus dish
• octopus as the thing being talked about
• the food item in a general but natural Spanish way

In food-related sentences, Spanish often keeps the article where English might not.

For example:

• El pollo está bueno. = The chicken is good.
• La sopa está caliente. = The soup is hot.

So el pulpo is completely normal here.

Pulpo is the normal Spanish noun for octopus. It is a masculine noun, so it takes:

• el pulpo
• delicioso

Because it is masculine singular, both the article and adjective match it.

In Spanish, when talking about an ingredient in a general way, the singular is often used:

• con patata
• con queso
• con cebolla

This can sound a bit like with potato / with potato as an ingredient.

That said, con patatas could also be possible in other contexts, especially if you are thinking of actual pieces or servings of potatoes. But con patata sounds very natural when describing a dish or combination of ingredients.

Since this is Spanish from Spain, patata is especially normal. In many parts of Latin America, papa is more common.

This is one of the most common learner questions.

Spanish often uses estar for how food tastes, smells, or seems at the moment:

• Está delicioso. = It tastes delicious / It is delicious right now.

Using ser would sound more like a general, inherent description:

• Es delicioso. = It is delicious by nature / in general

With food, estar is usually the more natural choice when giving an opinion about how it tastes when you eat it.

Other common examples:

• La sopa está muy buena.
• El café está frío.
• La tortilla está riquísima.

So está delicioso is exactly what you would expect for food.

Because the adjective must agree with the noun it describes.

The thing being described is el pulpo, which is:

• masculine
• singular

So the adjective must also be:

• masculine
• singular

That gives:

• delicioso

Compare:

• el pulpo está delicioso
• la patata está deliciosa
• los calamares están deliciosos
• las patatas están deliciosas

Here it means delicious.

With food, Spanish commonly uses several similar adjectives:

• delicioso = delicious
• rico = tasty
• buenísimo = really good
• riquísimo = very delicious / super tasty

So está delicioso is a strong, natural compliment about the food.

This is a very standard Spanish sentence structure:

• Mi madre = subject
• dice = main verb
• que = introduces the reported statement
• el pulpo con patata = subject of the second clause
• está delicioso = predicate

So the structure is basically:

[Subject] + [verb] + que + [subject] + [verb/adjective]

Spanish word order is flexible, but this version is neutral and natural. It sounds like a straightforward statement.

Yes, you could, but it sounds more marked or emphatic.

The original:

• Mi madre dice que el pulpo con patata está delicioso

is the most neutral and natural order.

If you say:

• Mi madre dice que está delicioso el pulpo con patata

you are putting more focus on está delicioso, almost like:

• My mother says the octopus with potato is delicious

So both are possible, but the original is the safer pattern for learners.

Because Spanish does not need a separate subject pronoun here. The noun phrase itself is already the subject:

• el pulpo con patata está delicioso

The subject is explicitly stated, so there is no need for an extra it like in English.

English requires:

• It is delicious

But Spanish can simply say:

• Está delicioso or
• El pulpo con patata está delicioso

depending on whether the subject is already clear.

Yes, it is natural, especially because patata is the usual word in Spain.

A Spaniard might also say things like:

• Mi madre dice que el pulpo con patata está muy bueno.
• Mi madre dice que el pulpo con patatas está delicioso.

Those are also natural depending on the speaker and the exact dish they have in mind.

So the sentence you have is grammatically correct and sounds normal in Spanish from Spain.