Learn Hardcore Hungarian: Szerintem ez a film rövid, de érdekes. - In my opinion this movie is short, but interesting.

Ez a film rövid, de érdekes. = “This film is short but interesting.”
(a neutral statement of fact)
Szerintem ez a film rövid, de érdekes. = “I think this film is short but interesting.”
(clearly marked as your opinion)

In conversation, Hungarians often leave out szerintem if the opinion is obvious from context, just like in English.

Does szerintem have to be at the beginning, or can it go somewhere else in the sentence?

It doesn’t have to be at the beginning. It’s fairly flexible:

Szerintem ez a film rövid, de érdekes.
Ez a film szerintem rövid, de érdekes.
Ez a film rövid, de szerintem érdekes.

All are grammatical. The nuance:

At the very start (Szerintem ...) – neutral, common: you’re lightly framing the whole sentence as your opinion.
After the subject (Ez a film szerintem ...) – still neutral; feels like a parenthetical “I’d say”.
Before érdekes (... de szerintem érdekes) – you subtly focus your opinion more on the “interesting” part.

In everyday speech, the first two are the most typical.

Why is there no word for “is” in Ez a film rövid, de érdekes.? Why don’t we say Ez a film van rövid?

In Hungarian, in present tense, 3rd person, with a simple “X is Y” statement, the verb van (“to be”) is omitted:

Ez a film rövid. – “This film is short.”
A film érdekes. – “The film is interesting.”

You only use van in these cases, for example:

With location/time:
- A film a moziban van. – The film is in the cinema.
With existence / there is:
- Van egy új film. – There is a new film.
In 1st or 2nd person:
- Én vagyok a tanár. – I am the teacher.
- Te vagy a tanár. – You are the teacher.
With negation or focus in 3rd person:
- A film nincs a moziban. – The film is not in the cinema.
- Nem ez a film az érdekes. – It’s not this film that is interesting.

So Ez a film van rövid is incorrect in standard Hungarian.

Why do we say ez a film and not just ez film?

In Hungarian, when you use a demonstrative (ez = this, az = that) before a noun, you almost always need the definite article as well:

ez a film – this film
az a film – that film
ezek a filmek – these films
azok a filmek – those films

Saying ez film sounds ungrammatical in standard Hungarian.

So the pattern is: > demonstrative (ez/az/ezek/azok) + article (a/az) + noun
> ez a film, az a könyv, ezek a házak, azok az emberek

What is the difference between ez a film and a film?

ez a film = “this film”, a specific film that’s near in context or situation (you’re pointing at it, or you just mentioned it clearly).
a film = “the film”, also specific, but without the “this/that” feeling; it’s already known from context, but not being highlighted as this one right here.

Examples:

Szerintem ez a film rövid. – I think this particular film is short.
Szerintem a film rövid. – I think the film (the one we’re talking about) is short.

In many contexts both are possible, but ez a film is more explicitly deictic (“this one”).

Why don’t the adjectives change form? Why is it rövid, érdekes and not something like “rövid‑valami”?

In Hungarian, predicate adjectives (adjectives used with “to be”: is short, is interesting) have a simple base form in the singular:

A film rövid. – The film is short.
A film érdekes. – The film is interesting.

They do not agree in gender (Hungarian has no grammatical gender) and in the singular they don’t show plural marking either.

However, in the plural, predicate adjectives do take a plural ending:

A filmek rövidek, de érdekesek. – The films are short but interesting.

So:

singular: rövid, érdekes
plural (as predicate): rövidek, érdekesek

When adjectives come before a noun (attributive use), they normally do not get a plural ending:

érdekes film – interesting film
érdekes filmek – interesting films (no érdekesek filmek)

Why is there a comma before de? Is that always required with de (“but”)?

In this sentence:

Szerintem ez a film rövid, de érdekes.

The comma is standard because de (“but”) is linking two separate predicates:

“(it is) short”
“(it is) interesting”

In Hungarian, when de connects two clauses or two full predicates, a comma before de is the norm, just like in English:

Sokat beszél, de keveset mond. – He talks a lot, but says little.

When de connects only smaller parts (e.g. words inside a simple phrase), usage can be looser, but in practice, people also tend to keep the comma in written language in cases like adjectives.

Other common words for “but” include:

viszont, azonban (more like “however / on the other hand”)
- Ez a film rövid, viszont érdekes.
- Ez a film rövid, azonban érdekes.

Does rövid mean “short” in all senses, like a short person, short time, short distance?

Rövid mainly means short in length or duration:

rövid film – short film
rövid történet – short story
rövid idő – short time
rövid út – short trip / short route
rövid haj – short hair

For a short person, Hungarian normally uses alacsony (“of low height”), not rövid:

Ő alacsony. – He/She is short (in height).

So:

Time, text, objects, hair, films, etc. ⇒ rövid
People’s height ⇒ alacsony

How would I say “I think this film is not short, but (it is) interesting.” in Hungarian?

A natural translation is:

Szerintem ez a film nem rövid, de érdekes.

Structure:

Szerintem – in my opinion / I think
ez a film – this film
nem rövid – not short
de érdekes – but (it is) interesting

You still omit van:

not: Szerintem ez a film nem van rövid (incorrect).
correct: Szerintem ez a film nem rövid.

If you really want to negate the thinking (“I don’t think this film is short …”), you’d usually rephrase:

Nem gondolom, hogy ez a film rövid, de érdekes.
– Literally: “I don’t think that this film is short, but it’s interesting.”

How would I say “I think this film is very short but quite interesting.”?

One natural version:

Szerintem ez a film nagyon rövid, de elég érdekes.

Breakdown:

nagyon rövid – very short
elég érdekes – quite interesting (literally “sufficiently interesting”)

Other options:

Szerintem ez a film nagyon rövid, de egészen érdekes. – very short but fairly / quite interesting.
Szerintem ez a film nagyon rövid, de meglepően érdekes. – very short but surprisingly interesting.

How would the sentence look in the plural: “I think these films are short but interesting.”?

In the plural you must mark demonstrative, noun, and predicate adjectives correctly:

Szerintem ezek a filmek rövidek, de érdekesek.

Details:

ezek – these
a – article (still required after the demonstrative)
filmek – films (plural of film)
rövidek – short (plural predicate adjective)
érdekesek – interesting (plural predicate adjective)

Compare:

singular: Ez a film rövid, de érdekes.
plural: Ezek a filmek rövidek, de érdekesek.