Mi abuela me enseñó a coser un botón con aguja e hilo.

Me is the indirect object pronoun meaning to me.

So the structure is:

• Mi abuela = subject
• me enseñó = taught me
• a coser un botón = to sew a button

A very common pattern is:

• enseñar algo a alguien = to teach/show something to someone
• enseñar a alguien a hacer algo = to teach someone to do something

So Mi abuela me enseñó... means My grandmother taught me...

Enseñó is the preterite form of enseñar, third person singular:

• yo enseñé = I taught
• tú enseñaste = you taught
• él/ella enseñó = he/she taught

The accent mark on ó is important. It shows both the correct spelling and the stress.

• enseñó = he/she taught
• enseño = I teach / I am teaching (present tense)

So the accent changes the meaning.

After enseñar when you mean teach someone to do something, Spanish normally uses:

• enseñar a + infinitive

So:

• me enseñó a coser = she taught me to sew

Without the a, it would sound wrong in standard Spanish.

Compare:

• Me enseñó costura = She taught me sewing / needlework
• Me enseñó a coser = She taught me how to sew

Coser means to sew.

Be careful not to confuse it with cocer, which means to cook/boil.

• coser = to sew
• cocer = to boil / cook

In Spain, these sound different:

• coser has an s sound
• cocer has a th sound in the second syllable, like Castilian c before e

So in Spain:

• coser ≈ ko-SER
• cocer ≈ ko-THER

Because y changes to e before a word beginning with an i sound.

So:

• aguja e hilo = needle and thread

This is the same rule as:

• padre e hijo = father and son

But there are exceptions when the word begins with an i-spelling but not really an i sound, for example:

• y hielo (not e hielo)

That is because hielo starts with a ye- sound, not a pure i sound.

Since hilo begins with an ee sound, e is used.

Spanish often leaves out the article when talking about tools or materials in a general way.

So:

• con aguja e hilo = with needle and thread

This sounds natural and idiomatic.

You could also say:

• con una aguja y un hilo

but that feels more like with a needle and a thread / with a needle and some thread, so it sounds a bit more specific or emphatic.

Un botón means a button, so it introduces it as one button / a button in general.

If both speaker and listener already knew which button was meant, you could say:

• el botón = the button

So the choice depends on context:

• coser un botón = sew a button / sew on a button
• coser el botón = sew the button

In this sentence, un botón is the neutral, natural choice.

Spanish often just says:

• coser un botón

and that already means to sew a button on in context.

If you want to say what you are sewing it onto, Spanish usually does that with a:

• coser un botón a la camisa = sew a button onto the shirt

So Spanish does not need a separate word exactly matching English on here.

Yes, but it changes the meaning.

• me enseñó = she taught me / she showed me

  • a completed action
  • often a one-time event or a finished learning moment

• me enseñaba = she used to teach me / she was teaching me

  • habitual, repeated, or ongoing in the past

So:

• Mi abuela me enseñó a coser un botón... = My grandmother taught me to sew a button
• Mi abuela me enseñaba a coser botones... = My grandmother used to teach me how to sew buttons

For this sentence, enseñó sounds right if you mean a completed act of teaching.

A few useful pronunciation notes for Spain:

• abuela = ah-BWEH-la
• enseñó = en-se-NYO
  
  • ñ sounds like the ny in canyon
• coser = ko-SER
• botón = bo-TON
• aguja = ah-GOO-ha
  
  • the j is the strong Spanish sound, like the ch in Scottish loch
• hilo = EE-lo
  
  • the h is silent

Also note that the final stressed syllables are marked in:

• enseñó
• botón

Because mi here is a possessive adjective meaning my:

• mi abuela = my grandmother

Mí with an accent is a pronoun used after prepositions:

• para mí = for me
• sin mí = without me

So:

• mi abuela = correct
• mí abuela = incorrect

It mainly describes how the sewing is done, so it goes with coser.

In other words:

• a coser un botón con aguja e hilo = to sew a button using needle and thread

Grammatically, Spanish often leaves this kind of relationship to context. Here the meaning is clear: the needle and thread are the tools used for sewing, not qualities of the button.

This is a very normal, natural order:

• Mi abuela me enseñó a coser un botón con aguja e hilo.

Spanish word order is somewhat flexible, but not every change sounds equally natural.

For example, you could move things around for emphasis, but the original version is the most straightforward for a learner.

A useful takeaway is:

• Subject: Mi abuela
• Indirect object pronoun: me
• Verb: enseñó
• Infinitive phrase: a coser un botón
• Instrument phrase: con aguja e hilo

So this sentence is a good model to copy.