Ĉiufoje, kiam la tajloro prenas mezuron, li skribas ĝin.

Ĉiufoje means every time or each time.

It is built from:

• ĉiu = every, each
• foje = time, occasion

So ĉiufoje literally means on every occasion. In this sentence, it introduces a repeated action: every time the tailor takes a measurement, he writes it down.

The comma separates the main idea from the time clause introduced by kiam.

The structure is:

• Ĉiufoje = every time
• kiam la tajloro prenas mezuron = when the tailor takes a measurement
• li skribas ĝin = he writes it

Esperanto often uses commas a bit more regularly than English, especially before subordinate clauses like one introduced by kiam.

Kiam means when.

In this sentence, it introduces a time clause:

• kiam la tajloro prenas mezuron = when the tailor takes a measurement

So the whole beginning means every time when..., which in natural English is just every time...

Esperanto often keeps this kind of structure very transparent:

• ĉiufoje, kiam... = every time that/when...

La tajloro means the tailor.

• tajloro = tailor
• la = the

The ending -o shows that tajloro is a noun.

In Esperanto, nouns always end in -o.

So:

• tajloro = tailor
• mezuro = measurement

This is one of the most regular features of Esperanto. If you see a word ending in -o, it is a noun.

Mezuron has the -n ending because it is the direct object of prenas.

• preni = to take
• prenas mezuron = takes a measurement

In Esperanto, the direct object usually gets -n:

• la tajloro prenas mezuron
• the tailor takes a measurement

Without -n, the grammar would be incomplete.

Because the sentence is talking about one measurement at a time.

• mezuron = a measurement / one measurement
• mezurojn = measurements

Since the action repeats each time, Esperanto treats each occasion individually: each time the tailor takes a measurement, he writes it.

Yes. It is a normal expression.

• preni = to take
• mezuro = measurement

So preni mezuron means to take a measurement, just like English.

Depending on context, it can mean measuring someone or noting down a specific measurement.

Yes, but Esperanto often uses a pronoun in the main clause just as English does.

• kiam la tajloro prenas mezuron = when the tailor takes a measurement
• li skribas ĝin = he writes it

Using li avoids repeating la tajloro again. It sounds natural and clear.

Ĝin refers to mezuron.

So:

• mezuron = the measurement
• ĝin = it

The sentence means that after taking the measurement, the tailor writes it down.

Because ĝin is the direct object of skribas.

• li skribas ĝin = he writes it

Just like nouns, pronouns also take -n when they are direct objects:

• li vidas lin = he sees him
• li skribas ĝin = he writes it

Esperanto often uses the present tense for repeated or habitual actions.

Here, the sentence describes something that happens regularly:

• every time the tailor takes a measurement
• he writes it down

So prenas and skribas are both present tense because this is a general habit, not one single event in the past.

Yes, Esperanto word order is fairly flexible, but this version is the most straightforward and natural.

Standard order here is:

• Ĉiufoje, kiam la tajloro prenas mezuron, li skribas ĝin.

You could sometimes move parts around for emphasis, but learners should treat this as the normal pattern:

• time expression
• subordinate clause
• main clause

Yes, in context it is enough.

Skribi means to write, and here ĝi refers to the measurement. In natural English, we often say write it down, but Esperanto may simply say skribi ĝin when the meaning is obvious.

If someone wanted extra emphasis, they could use a fuller expression in another context, but here li skribas ĝin is perfectly natural.

Yes. Learners can think of Ĉiufoje, kiam... as a very common pattern meaning whenever... or every time that...

So a helpful way to read it is:

• Ĉiufoje, kiam X okazas, Y okazas.
• Every time X happens, Y happens.

That pattern is exactly what this sentence uses.