There are two concepts in Esperanto which new learners often mix up – not because they are all that similar to each other – but because they both translate approximately to “himself” (herself, themselves, et cetera.) These are the particle mem and the reflexive pronoun si.

Mem-o to myself

It’s all for emphasis

Of these two, mem is the simplest one to explain. It’s used for emphasis – usually of the word that comes before it. Sort of a verbal underlining.

Hodiaŭ mem mi veturos al Tours – On this very day I will drive to Tours.

Hieraŭ mem vi diris, ke… – Only yesterday you said …

kvazaŭ la ĉambro mem kuntiradus la brovojn en serioza meditado – as if the very room were furrowing its brows in serious contemplation.

Tiu vorto troviĝas en kelkaj vortaroj, sed ne en la lingvo mem. – This word is found in a few dictionaries, but not in the language proper / not in the actual language.

Without mem, the meaning would be almost the same. It’s just that the key element would not have the same emphasis.

Today I will drive …

Yesterday you said …

As if the room were furrowing its brows …

… but not in the language.

I’m hoping that by this point, many of you are asking “but what about ‘-self’?” You may have learned in your basic Esperanto course that mem means “himself, herself, itself.” I intentionally avoided these words in my examples to show how mem can add emphasis without comparing it to “-self”. Ultimately we want to express ideas in Esperanto, not translate words. Just a few more more examples to show where “-self” comes in.

kvazaŭ la ĉambro mem … – as if the room itself …

sed ne en la lingvo mem – but not in the language itself.

Mi mem ne havas biciklon, sed mia frato havas – I myself don’t have a bike, but my brother has one.

Remember that mem is about emphasizing another word in the sentence. There is a secondary meaning of mem that follows from this, similar to how it works in English. If Petro mem built the house, that means that he did it himself. He didn’t pay someone to do it, and he quite possibly didn’t have any help. (“All by himself.”)

She will “si” for herself

Si “reflects” back on the subject

The term “reflexive” means that the subject and the object are the same thing. Imagine that I’d just waxed the table and I can see my reflection in it. If I were an Esperanto-speaking caveman, I might say something like this.

Tomaso vidas Tomason – Thomas sees Thomas.

In Esperanto, we can just plug in mi for Tomaso if we don’t want to sound like a caveman. However, in English, something funny happens.

Mi vidas min – I see myself.

The “-self” here has nothing to do with emphasis, so it is not mem. It is called a “reflexive pronoun” in English. In Esperanto, if the subject is mi, ni, or vi, we don’t have to do anything special here. However, if it’s “third person” (just about anything but mi, ni, or vi), that’s where si comes in.

Mi vidas min – I see myself.

Vi vidas vin – You see yourself.

Li vidas sin – He sees himself.

Note that there is not a mem to be seen here. The “-self” here has nothing to do with emphasis, but only means that the subject and object are the same thing. Remember that si is only for third person – that is, not with mi, ni, or vi. Also note that si must be used any time we’re referring to the subject. If we use a different pronoun, it means a different person.

Mi kombas al mi la harojn. – I comb my hair.

Ŝi kombas al si la harojn. – She combs her hair.

Mi kombas al ŝi la harojn. – I comb her hair (not my own.)

Ŝi kombas al ŝi la harojn. – She combs another woman’s hair (not her own.)

(Bonvolu ne ŝerci en la komentejo pri kalvuloj.)

Another common use of si is in the possessive pronoun sia. Again, this always refers to the subject. It is only used in “third person”.

Mi venis kun mia frato. – I came with my brother.

Ŝi venis kun sia frato. – She came with her brother.

And again, if you don’t use sia, the listener will assume you’re not talking about the subject.

Ŝi venis kun ŝia frato – She came with the brother of some other woman or girl we mentioned previously.

Si and mem together

There will be times when you’ll want to do both things at once – refer to a third-person subject and emphasize that it’s this very subject (la subjekto mem) that you’re referring to. Enter “si mem.”

We could probably do an entire blog post on si and mem together (and I will if there are enough comments requesting this). For now I’ll just say that many of the times we see mem with si, the mem is actually superfluous, but by far not always. Just remember that this is an emphasized reference to the subject.

One of the more common and useful ways to use these together is in expressions like per si mem, which means approximately “in and of itself.”

Se vorto per si mem estas internacia, tiam ĉiu havas la rajton uzi tiun ĉi vorton – if a word is international in and of itself, then everybody has the right to use this word.

Esperanto per si mem ne povas ŝanĝi la destinon de la homaro – Esperanto can’t change the humanity’s destiny all by itself.

Express ideas – Don’t translate

There are other good descriptions of mem and si out there (I’ve hot-linked the descriptions in PMEG). My goal isn’t to duplicate those descriptions, but rather to highlight the difference to avoid some of the typical confusion which English-speaking learners encounter. When you find yourself thinking about how to translate “-self” into Esperanto, it’s best to take a step back and ask what idea you’re trying to express. If you want to emphasize a word, use mem. If you want to refer to the subject (and if the subject is not I, you, or we), use si.