Learn Hardcore Icelandic: Við tölum stundum saman um leyndarmál. - We sometimes talk together about secrets.

Við – we (subject pronoun, nominative plural)
tölum – talk / speak (1st person plural present of tala)
stundum – sometimes (adverb of frequency)
saman – together / with each other (adverb)
um – about (preposition governing accusative)
leyndarmál – secret / secrets (neuter noun; here indefinite, can mean one or more)

So literally: We talk sometimes together about secret(s).

Why is it tölum and not tala or talar?

Tala is the infinitive: að tala = to talk, to speak. It conjugates in the present tense like this:

ég tala – I talk
þú talar – you (sg.) talk
hann / hún / það talar – he / she / it talks
við tölum – we talk
þið talið – you (pl.) talk
þeir / þær / þau tala – they talk

So you use tölum because the subject is við (we), 1st person plural.

The vowel change a → ö (tala → tölum) is a common pattern in Icelandic; historically it comes from a sound change (u-umlaut). You just need to learn it as part of this verb’s normal conjugation.

Is this sentence present simple or present continuous? Could it also mean we are talking?

Icelandic simple present (tölum) covers both:

habitual / general: We (sometimes) talk together about secrets.
present-in-the-moment: We are (right now) talking together about secrets.

If you really want to emphasize “right now, currently”, you can also say:

Við erum að tala saman um leyndarmál. – literally We are to talk together about secrets, functionally We are talking together about secrets.

But in many contexts, Við tölum stundum saman um leyndarmál is naturally understood as talking that happens from time to time, not necessarily right at this moment. Context decides.

Why do we need við? Could Icelandic drop the pronoun like Spanish (Hablamos)?

No, standard Icelandic does not normally drop subject pronouns. You generally must say:

Við tölum, not just Tölum, when you mean we talk.

So Icelandic is more like English or German here, not like Spanish or Italian. The verb form tölum tells you it’s we, but the language still requires you to say við in normal sentences. (You can drop it in some commands, set phrases, etc., but not in a neutral declarative sentence like this.)

Why is stundum (sometimes) in that position, and can it move?

In the sentence Við tölum stundum saman um leyndarmál, the “middle” of the clause goes like this:

tölum (verb)
stundum (adverb of frequency)
saman (adverb of manner, “together”)

This is a very natural order: verb → frequency adverb → manner adverb.

You can move stundum for emphasis or style:

Stundum tölum við saman um leyndarmál. – Sometimes we talk together about secrets.
– Emphasizes sometimes by putting it at the beginning.
Við tölum saman stundum um leyndarmál.
– Grammatically possible, but sounds less neutral; most learners should stick to the first two versions.

The original order (Við tölum stundum saman…) is very natural and a safe default.

What exactly does saman add? Isn’t við tölum already “we talk”?

Við tölum on its own just says we talk / we speak (with no information about to whom).

Tala saman is more specific and idiomatic. It means talk together, talk to each other, have a conversation. So:

Við tölum – We talk / we speak (in general; could be about our ability to speak, or that we give speeches, etc.).
Við tölum saman – We talk with each other / we have conversations.

In everyday speech about people communicating with each other, you will very often see tala saman. The saman is not optional if you want that “with each other” nuance.

What is the function of um here? Why is it um leyndarmál and not something else?

The preposition um is the usual way to say about (in the sense of “on the topic of”) in Icelandic:

tala um eitthvað – talk about something
lesa um eitthvað – read about something
hugsa um einhvern – think about someone

So:

tölum … um leyndarmál = talk … about secrets / a secret.

Grammatically, um governs the accusative case. The noun leyndarmál is a neuter noun whose form does not change between nominative and accusative in the singular, so you don’t see a visible case ending here—but it is grammatically accusative after um.

Is leyndarmál singular or plural here? How can I tell?

Leyndarmál is a neuter noun with the same form for:

nominative singular: leyndarmál – a secret
accusative singular: leyndarmál
nominative plural: leyndarmál – secrets
accusative plural: leyndarmál

So in um leyndarmál, the form by itself does not tell you whether it’s “about a secret” or “about secrets”; both are possible. Context (wider text, number, other words) would decide:

um eitt leyndarmál – about one secret
um mörg leyndarmál – about many secrets

By default, learners usually translate um leyndarmál as about secrets (in general) unless context clearly indicates just one.

What does leyndarmál literally mean? How is it formed?

Leyndarmál is a compound noun:

leynd – secrecy, concealment, being hidden
– In the compound, it appears as leyndar-, which is the genitive form.
mál – matter, affair, issue; speech; case.

So leyndarmál literally means something like a matter of secrecy or a secret matter. From that, it simply comes to mean a secret.

This kind of genitive + mál compound is very common in Icelandic (and you will see many other compounds built on -mál).

Why is there no word for a or the in um leyndarmál?

Icelandic does not use separate words for a and the like English. Instead:

There is no article word for a/an at all; the bare noun often functions as indefinite.
The definite article (the) is usually attached as an ending to the noun.

For leyndarmál:

um leyndarmál – about a secret / about secrets (indefinite)
um leyndarmálið – about the secret (definite singular)
um leyndarmálin – about the secrets (definite plural)

In your sentence, um leyndarmál is indefinite: no -ið or -in ending, so it is not the.

If I want to say We talk about secrets, can I leave out saman?

Yes, you can say:

Við tölum stundum um leyndarmál.

This simply means We sometimes talk about secrets (it does not explicitly highlight the “with each other” aspect, although it will often be understood that way in context).

The difference:

Við tölum stundum um leyndarmál. – neutral “we talk about secrets” (e.g. as a topic).
Við tölum stundum saman um leyndarmál. – “we sometimes talk with each other about secrets”; emphasizes the mutual conversation.

Both are correct; saman just adds the idea that it’s a two‑way conversation among the við group.

How would the sentence change if I front the adverb stundum for emphasis?

You can say:

Stundum tölum við saman um leyndarmál.

This is fully grammatical and natural. It puts special emphasis on stundum:

Stundum – Sometimes (and not always)

So you have two very natural word orders:

Við tölum stundum saman um leyndarmál. – neutral; subject first.
Stundum tölum við saman um leyndarmál. – emphasizes sometimes.

Both mean the same in content; the second just highlights the frequency.

How is this sentence pronounced, and where is the stress?

In careful IPA, one common pronunciation would be roughly:

Við – [vɪːð] or [vɪð] (v like English v, ð like th in this)
tölum – [ˈtœːlʏm]
stundum – [ˈstʏntʏm] or [ˈstʏndʏm] (the d can be weak)
saman – [ˈsaːman]
um – [ʏm] (short vowel, lips rounded)
leyndarmál – [ˈlei(nt)tarˌmauːl] (the nd often has a very light t component)

Important points:

In Icelandic, stress is almost always on the first syllable of each word: VÍð, TÖlum, STUNdum, SÁman, LEYndar, MÁL.
The whole phrase flows together in natural speech, but each word still has initial stress.