Mi voto cuenta.

Mi without an accent is the possessive adjective meaning my.

• mi voto = my vote

Mí with an accent is a pronoun used after prepositions:

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

So in Mi voto cuenta, you need mi because it is describing the noun voto.

Because yo means I, and that is not the subject of this sentence.

The subject here is mi voto = my vote.
So the verb has to agree with voto, which is third person singular:

• mi voto cuenta = my vote counts

If you said yo, the verb would need to match yo:

• yo cuento = I count / I am counting
• yo voto = I vote

So Yo voto cuenta is not grammatically correct.

Cuenta is the third-person singular present tense of contar.

Here is the relevant part of the conjugation:

• yo cuento
• tú cuentas
• él/ella cuenta
• mi voto cuenta

Since voto is singular, Spanish uses cuenta.

Yes, but in this kind of sentence contar often means more than just counting numbers. It can also mean:

• to count
• to matter
• to be taken into account

So Mi voto cuenta can be understood as:

• My vote counts
• My vote matters

This is a very common use of contar.

Because mi already acts as a determiner.

In Spanish, you normally do not use an article before a noun when it already has a possessive adjective like mi, tu, su, etc.

So:

• mi voto = correct
• el mi voto = not correct in standard modern Spanish

This works like:

• mi casa = my house
• mi opinión = my opinion

Voto usually means vote, especially in political or election contexts.

But it can also mean vow in some contexts, especially formal or religious ones.

Examples:

• emitir un voto = to cast a vote
• hacer un voto = to make a vow

In Mi voto cuenta, the normal meaning is clearly vote.

A simple pronunciation guide is:

• mi → mee
• voto → BOH-toh
• cuenta → KWEN-tah

A few useful notes:

• In Spanish from Spain, v and b are pronounced very similarly.
• The c in cuenta is a hard k sound because it comes before u.
• The stress is:
  • VO in voto
  • CUEN in cuenta

So overall: mee BOH-toh KWEN-tah

Yes. That would also be correct, but it means something slightly different in tone.

• Mi voto cuenta = My vote counts / matters
• Mi voto es importante = My vote is important

The version with cuenta sounds more natural in slogans, civic messages, and discussions about participation, because it emphasizes that the vote has an effect.

Yes, sometimes. Literally it refers to an actual vote, but it can also be used more broadly in situations where a person wants to stress that their opinion or choice should be considered.

For example, someone might use it figuratively in a group decision, although in that case Spanish speakers might also say:

• Mi opinión cuenta = My opinion matters
• Mi voz cuenta = My voice matters

So Mi voto cuenta is most naturally about voting, but the idea can extend beyond that.

You usually would not say Cuenta mi voto in a neutral statement.

The normal word order is:

• Mi voto cuenta

Spanish can change word order for emphasis or in poetic/stylized language, but for a clear everyday sentence, Mi voto cuenta is the natural choice.

If you want emphasis, Spanish more often adds words like:

• Mi voto sí cuenta = My vote really does count

Because the speaker is talking about one vote: my vote.

• Mi voto cuenta = My vote counts
• Mis votos cuentan = My votes count

In most normal situations, one person has one vote, so the singular is the expected form.