The diacritical accent or diacritical tilde, consists of, by means of a tilde, differentiating words that are written and pronounced the same, but have different meanings.
This category includes, for example, monosyllabic words, which as a rule we know are not marked.
Let's then exemplify the case of monosyllables one by one:
My / My
It has an accent mark when it is a personal pronoun: “They told me something else”.
It is not accentuated when we use it with the possessive adjective function: “This is my house”.
Does not have a tilde in the case of referring to the musical note “mi”.
You / You
Like “me”, it has an accent mark when used as a personal pronoun: “You are very kind”.
Also the same as before, it does not have an accent mark if it is used as a possessive adjective: “Your car won't let me pass”.
He/He
It will have a tilde when it acts as a personal pronoun: “He took me there”.
It will not have the tilde when it is a definite article: “I liked today's program”.
I know / I know
Carry a tilde when used as a verb, to be or to know: “I know you will pass”.
It doesn't when it acts as a personal pronoun, reflex pronoun or reciprocal pronoun. Nor when it is a sign of impersonality or passivity: “They spent the whole day working”.
From / Give
When it is a verb, it will have an accent: “She told him to give it to her”.
When it is a preposition, it will not have a tilde: “The light outside does not work”.
Yes / Yes
It is marked when it is an adverb of affirmation: “Yes, I agree”.
Also, when it comes to the third person personal pronoun: “he is very busy with himself.”
When it is a conjunction (conditional or interrogative), it will not have a tilde: “If it seems appropriate I will do it”.
It will not have a tilde in the case of referring to the musical note “si”.
More / More
This word will be checked when it means an adverb of quantity: “I like the other option better”.
On the other hand, it will not be marked when it is synonymous with “but”, that is, when it is an adversative conjunction: “I like this, but the previous one was better”.
Tea / Tea
It has a tilde when referring to the infusion: “At five o'clock we will have tea”.
Does not have an accent mark when referring to the personal pronoun: “Does it seem alright to you?”
O / Ó
This disjunctive conjunction (which indicates alternation), will only be checked when there are numbers around it. This serves to avoid ambiguity with the number “0” given its similarity in form: “Was it 2 or 3 people?”
Solo / Solo
It will be written with a tilde when it is an adverb of manner and means “only” or “only”: “I only wanted to help”.
It will be written without a tilde when it is an adjective and means “without company” or “alone”: “He created everything that he did alone.”
Still / Still
This word will have an accent when it means in the sentenceadverb of time, that is, synonymous with “yet”: “The party hasn't started yet”.
It will not have a tilde when this word is a component of the conjunctive mood “even when”: “Even when I forbade it, it didn't pay attention to me”.
Another case in which it will not have an accent is when it has a prepositional value and means «until» or «even»: "It was difficult even for the most experienced".
Demonstratives (This/That/That)
They can be adjectives or pronouns.
They will have a tilde when they act as pronouns: “I prefer this one”.
They will not have accents when they act as adjectives: “This morning is beautiful”.
