Learn Hardcore Croatian: Njegov glas je preglasan u tihoj sobi. - His voice is too loud in the quiet room.

So “glas” can mean “a voice” or “the voice”, and “soba” can be “a room” or “the room”, depending on what was already mentioned or is obvious in the situation.

You don’t add anything in Croatian to mark “the” explicitly.

Why is it “njegov glas” and not something like “on glas” or “njega glas”?

on = he (subject pronoun)
njega = him (genitive/accusative form)
njegov = his (possessive adjective)

You need a possessive form to say “his voice”, so you use njegov, which behaves like an adjective and agrees with the noun:

njegov glas – his voice (masculine singular)
njegova soba – his room (feminine singular)
njegovo dijete – his child (neuter singular)

What is the difference between “glasan” and “preglasan”?

glasan = loud
preglasan = too loud / overly loud

The prefix pre- in front of adjectives usually means “too / excessively”:

skup – expensive → preskup – too expensive
malen – small → premalen – too small
umoran – tired → preumoran – too tired

So “Njegov glas je preglasan” specifically means the loudness is excessive, not just “loud.”

Could I say “previše glasan” instead of “preglasan”?

Yes:

previše glasan = too loud
preglasan = too loud

They mean almost the same. Some nuances:

preglasan is shorter and very natural in speech.
previše glasan literally means “too-much loud”, which can sound a bit more explicit or emphatic.

Both are correct:
Njegov glas je preglasan u tihoj sobi.
Njegov glas je previše glasan u tihoj sobi.

Why is it “u tihoj sobi” and not just “u tiha soba” or “u tiha sobu”?

Because the preposition u (“in”) with a static location (being inside somewhere) takes the locative case.

soba (room), nominative: soba
locative singular: sobi

The adjective tih (quiet) must agree with soba in gender, number and case:

feminine, singular, locative adjective ending: -oj → tihoj

So you get:

u
- tihoj
  - sobi
    (in + quiet + room, all in the correct locative forms)

“u tiha soba” or “u tiha sobu” are ungrammatical in this context.

Why is the adjective “tihoj” ending in -oj? How does that work?

tih → tiha → tihoj is the feminine singular pattern of the adjective “quiet”:

Nominative (basic dictionary form, for feminine singular): tiha – quiet
Locative (feminine singular): tihoj – in the quiet …

Common feminine singular adjective endings:

Nominative: -a (tiha, dobra, mala)
Locative: -oj (tihoj, dobroj, maloj)

So tihoj is just “quiet” in the form required by u + locative plus a feminine noun (soba).

What case is “sobi” in, and why does it end in -i?

sobi is locative singular of soba (a room).

Nominative singular: soba – room
Locative singular: (u) sobi – in (the) room

For many feminine nouns ending in -a, the locative singular ends in -i:

škola → u školi (school → in school)
kuća → u kući (house → in the house)
soba → u sobi (room → in the room)

You need this locative because of the preposition u with a stationary location.

Could the word order be different, like “U tihoj sobi je njegov glas preglasan”?

Yes. Croatian word order is flexible. All of these are grammatically correct:

Njegov glas je preglasan u tihoj sobi.
Njegov glas u tihoj sobi je preglasan.
U tihoj sobi je njegov glas preglasan.

The differences are mainly emphasis:

Starting with “U tihoj sobi…” highlights the location first.
Leaving it at the end, “…u tihoj sobi”, feels more neutral, like English.

Meaning is the same; the nuance is which part of the sentence you mentally foreground.

Can “je” be dropped, like in some other Croatian sentences?

In everyday speech, Croatians sometimes omit the present tense of “biti” (to be), especially in the 3rd person:

Njegov glas preglasan u tihoj sobi.

People might say this in casual conversation, and it will be understood, but:

In standard / written Croatian, you should keep “je”.
For learners, it’s safer and more correct to always include the verb “biti” in such sentences:

Njegov glas je preglasan u tihoj sobi.

Why are “njegov” and “preglasan” both in the masculine form? Do they have to match something?

Yes, they both must agree with glas (voice), which is:

masculine
singular
nominative (subject)

So:

njegov – his (masculine singular nominative, agreeing with glas)
preglasan – too loud (masculine singular nominative, also agreeing with glas)

If the noun changed, the forms would change too:

Njegova soba je tiha. – His room is quiet. (soba = feminine → njegova, tiha)
Njegovo dijete je glasno. – His child is loud. (dijete = neuter → njegovo, glasno)

How do you pronounce “njegov glas je preglasan u tihoj sobi”?

Rough pronunciation guide (stressed syllables in bold):

NJEgov – nye-gov (nj like Spanish ñ in niño; j like English y in yes)
glas – like English glass but shorter a
je – like “yeh”
preGLasan – preh-glah-san (each a like in father)
u – like “oo” in food
TIhoj – tee-hoy (h is pronounced, j again like y)
SObi – soh-bee

Altogether: NJE-gov glas je pre-GLA-san u TI-hoj SO-bi.