Magistra iis libros dat, qui in bibliotheca tacent.

Latin shows grammatical roles mainly through case endings, not just word order.

• magistra is nominative singular, so it is the subject
• libros is accusative plural, so it is the direct object
• iis is dative plural, so it is the indirect object
• dat is 3rd person singular, which matches magistra

So the structure is:

• magistra = the one giving
• libros = the thing being given
• iis = the people receiving them

iis is the dative plural of is, ea, id, a very common pronoun meaning he / she / it or that / those, depending on context.

Here it means something like to those or to them, because it is the indirect object of dat.

A learner should also know that iis is often spelled eis as well. Both forms are acceptable; they mean the same thing.

This is a very common Latin pattern:

• iis = to those
• qui = who

So iis ... qui ... means to those ... who ...

Latin often uses an antecedent plus a relative pronoun:

• iis belongs to the main clause: Magistra iis libros dat
• qui in bibliotheca tacent is the relative clause describing those people

English does this too, although we may not always notice it clearly: the teacher gives books to those who are quiet in the library.

Because the case of a relative pronoun depends on its job inside its own clause, not on the case of its antecedent.

Here:

• iis is dative because it is the indirect object of dat
• qui is nominative because it is the subject of tacent

So although qui refers back to iis, it does not copy the dative case.

A very useful rule is:

A relative pronoun agrees with its antecedent in gender and number, but its case depends on its function in the relative clause.

It refers to iis, the people receiving the books.

Grammatically, qui is masculine plural, and that could in theory match either iis or libros, because libros is also masculine plural. But the meaning makes it clear:

• qui ... tacent = who are silent
• people can naturally be silent in a library
• books are not the intended idea here

So the relative clause describes the recipients, not the books.

qui is masculine plural.

Latin uses the masculine plural for:

• a group of males
• a mixed group
• sometimes a group whose gender is not being specifically emphasized

So qui here means the recipients are understood as masculine or mixed.

If the group were specifically all female, Latin could use quae instead.

Because in takes different cases depending on the meaning:

• in + ablative = in / inside / at a place
• in + accusative = into a place, showing motion toward it

Here the sentence means the people are already in the library, so Latin uses the ablative:

• in bibliotheca = in the library

If it meant into the library, it would be in bibliothecam.

• dat is 3rd person singular present active of do, dare = gives
• tacent is 3rd person plural present active of taceo, tacere = are silent / keep quiet

They match their subjects:

• magistra dat = singular subject, singular verb
• qui tacent = plural subject, plural verb

No. Latin word order is much freer than English word order because the endings already show each word’s role.

This sentence could be rearranged in several ways without changing the basic meaning, for example:

• Magistra iis libros dat, qui in bibliotheca tacent.
• Magistra libros iis dat, qui in bibliotheca tacent.
• Iis libros dat magistra, qui in bibliotheca tacent.

The chosen order can affect emphasis, but not the core grammar.

Not very much for the grammar.

The comma here simply helps the reader see where the relative clause begins:

• main clause: Magistra iis libros dat
• relative clause: qui in bibliotheca tacent

In modern printed Latin, punctuation is added for clarity, but Latin grammar does not depend on commas in the same way English often does.