Learn Hardcore Icelandic: Ég vil að barnið mitt noti alltaf hjálm svo það lendi ekki í slysi. - I want my child to always use a helmet so it does not get into an accident.

Without að, the Icelandic sentence is ungrammatical in this structure. You can drop að only if the next verb is an infinitive directly governed by vil:

Ég vil nota hjálm. – I want to use a helmet. (no extra subject, no að)

Why are the verbs noti and lendi used instead of notar and lendir?

Noti and lendi are in the present subjunctive, not the normal present indicative.

Indicative (3rd person singular, “normal present”):
- hann notar – he uses
- hann lendir – he ends up / gets into
Present subjunctive (3rd person singular):
- hann noti
- hann lendi

In this sentence, both verbs are in subordinate clauses that express wish / intention / prevention, so Icelandic uses the subjunctive:

Ég vil að barnið mitt noti alltaf hjálm…
I want my child to always use a helmet… (wish / desire)
…svo það lendi ekki í slysi.
…so that it does not end up in an accident. (a hoped-for or prevented outcome)

The present subjunctive is very common:

after verbs of wanting, asking, ordering (vilja, biðja, skipa, osfrv.)
in clauses expressing purpose, fear, doubt, possibility

So noti and lendi signal that these things are not just statements of fact, but things you want to happen (or not happen).

Why is it barnið mitt instead of mitt barn, and what exactly does barnið mean?

Barnið mitt literally means “the child my”, which is the normal way to say “my child” in Icelandic.

barn – child (indefinite)
barnið – the child (definite; -ið is the definite article attached to the noun)
mitt – my (neuter, singular, to match barn)

Typical pattern: definite noun + possessive pronoun

húsið mitt – my house
bíllinn minn – my car
barnið mitt – my child

You can say mitt barn, but:

barnið mitt is the usual neutral way to say my child.
mitt barn adds more emphasis (my child in contrast to others, slightly more emotional, poetic, or contrastive).

Also, note the form mitt (not minn or mín). The possessive pronoun agrees with the grammatical gender of the noun:

barn is neuter → mitt barn / barnið mitt
bíll (m.) → bíllinn minn
bók (f.) → bókin mín

Why is the pronoun það used for “the child” and not hann or hún?

In Icelandic, personal pronouns agree with the grammatical gender of the noun they refer to, not with the real-world sex of the person, unless you switch to a specifically gendered word.

barn “child” is neuter, so its pronoun is það (it).
- barnið… það – the child… it

If you use gendered nouns like drengur (boy) or stelpa (girl), then you use hann or hún:

Ég vil að drengurinn minn noti alltaf hjálm svo hann lendi ekki í slysi.
Ég vil að stúlkan mín noti alltaf hjálm svo hún lendi ekki í slysi.

But as long as you say barnið, the grammatically correct pronoun is það.

Why is hjálm used without a definite article (not hjálminn)?

Here hjálm is indefinite and generic – it means “a helmet / helmets in general”, not “the specific helmet”.

hjálmur – helmet (nominative singular)
hjálm – helmet (accusative singular, the form you see here)
hjálmurinn / hjálminn – the helmet (definite)

In nota hjálm, you’re talking about the general habit of using a helmet:

Ég vil að barnið mitt noti alltaf hjálm.
I want my child to always use (a) helmet. (any helmet, as a rule)

If you say:

Ég vil að barnið mitt noti alltaf hjálminn.

that implies a particular helmet that both speaker and listener have in mind (for example, the child’s own helmet).

Why is the adverb alltaf placed after noti, as in noti alltaf hjálm? Could it go somewhere else?

The most natural place for alltaf (always) in a clause like this is after the finite verb:

(að) barnið mitt noti alltaf hjálm – my child always uses a helmet

General pattern in neutral word order:

subject – finite verb – adverb – object
- Hann borðar alltaf morgunmat. – He always eats breakfast.
- Hún talar aldrei ensku. – She never speaks English.

You might hear or see other positions, but they either sound less natural or add emphasis:

Ég vil að barnið mitt alltaf noti hjálm. – possible, but marked; heavy emphasis on always.
Ég vil að barnið mitt noti hjálm alltaf. – also possible, but sounds a bit less neutral; alltaf then feels more attached to “wearing a helmet” as a whole.

The sentence as given, …noti alltaf hjálm…, is the standard, neutral word order.

What exactly does svo mean here, and how is it different from til að or þannig að?

In this sentence svo introduces a clause of purpose / desired result:
svo það lendi ekki í slysi – so that it doesn’t end up in an accident.

Here svo is basically “so (that)”.

Ég vil að barnið mitt noti alltaf hjálm svo það lendi ekki í slysi.
I want my child to always use a helmet so (that) it doesn’t get into an accident.

You could also say:

…til að það lendi ekki í slysi. – in order that it doesn’t get into an accident
…þannig að það lendi ekki í slysi. – in such a way that it doesn’t get into an accident

Nuances:

svo (að) – very common, fairly neutral, can express purpose or consequence.
til að – more explicitly purpose (“in order to”).
þannig að – often “so that / in such a way that”, sometimes more about the manner leading to a result.

In everyday speech, svo (að) is extremely common in this kind of sentence.

Do we need að after svo (svo það lendi… vs svo að það lendi…)?

No, að is optional here. Both are correct:

svo það lendi ekki í slysi
svo að það lendi ekki í slysi

In modern spoken and written Icelandic, it’s very common to omit að after svo:

Hann fór fyrr svo hann missti ekki af strætó.
= Hann fór fyrr svo að hann missti ekki af strætó.

Adding að can sound a bit more formal or explicit, but there is no change in meaning in this kind of sentence.

Why does ekki come after lendi (in svo það lendi ekki í slysi) instead of before the verb?

In standard Icelandic word order, the negation ekki usually comes after the finite verb in a normal clause:

Hann kemur ekki. – He is not coming.
Hún vill ekki fara. – She does not want to go.
(að) hann lendi ekki í slysi. – that he does not end up in an accident.

So in svo það lendi ekki í slysi, we have:

það (subject)
lendi (finite verb, subjunctive)
ekki (negation)
í slysi (prepositional phrase)

You can move ekki around for special emphasis in some structures, but það ekki lendi í slysi would be unusual here and would normally require a different structure (like fronting something for emphasis). The given order is the neutral, grammatical one.

Why is it í slysi and not í slys or some other form of slys?

Í slysi uses the dative singular of slys:

slys – accident (nominative / accusative singular)
slysi – dative singular
slyss – genitive singular

The preposition í can take dative or accusative, depending on the meaning:

í + accusative – movement into something
- Hann keyrði í tré. – He drove into a tree.
í + dative – location or state (being in something)
- Hann er í skólanum. – He is at school.
- Hún lenti í slysi. – She ended up in an accident. (state)

Here, lenda í slysi describes being in the state of having an accident / involved in an accident, not moving into a physical place, so dative (slysi) is required.

Could we say í slysinu instead of í slysi? Would that change the meaning?

Yes, í slysinu is grammatically correct, but it feels more specific:

í slysi – in an accident, any accident in general (indefinite)
í slysinu – in the accident, a particular accident known from context

In your sentence:

…svo það lendi ekki í slysi.
– …so that it doesn’t get into an accident (at all, in general).

If you said:

…svo það lendi ekki í slysinu.

it would sound like you are talking about one specific, known accident (for example, something that is expected or being discussed), which usually isn’t what you mean here.

You might also hear strong negatives like:

…svo það lendi ekki í neinu slysi. – …so that it doesn’t get into any accident at all.

What is the difference between Ég vil and Mig langar if both can be translated as “I want”?

Both can express wanting, but they are used somewhat differently:

Ég vil
- að-clause / infinitive / noun
- More direct, sometimes stronger; “I will / I want / I wish for”.
- Often used when you’re stating a desire or intention, or giving an instruction.
- Examples:
  - Ég vil drekka kaffi. – I want to drink coffee.
  - Ég vil að þú komir. – I want you to come.
Mig langar
- í + accusative (for wanting something) or að + infinitive (for wanting to do something)
- Literally “it longs me”, more like “I feel like / I would like”.
- Often sounds softer, more about a feeling or wish than about will/command.
- Examples:
  - Mig langar í kaffi. – I feel like (having) coffee.
  - Mig langar að fara heim. – I’d like to go home.

In your sentence, Ég vil að barnið mitt noti alltaf hjálm… is appropriate because it is a rule/intention you have for your child. You could say Mig langar til þess að barnið mitt noti alltaf hjálm, but that sounds more like a personal wish than a rule you’re setting.

What case is barnið mitt in inside the clause að barnið mitt noti alltaf hjálm?

Inside the subordinate clause að barnið mitt noti alltaf hjálm, barnið mitt is the subject of noti, so it is in the nominative case.

For neuter nouns like barn, the nominative and accusative singular look the same:

nominative singular: barnið
accusative singular: barnið

So even though the form doesn’t change, its function here is nominative (subject):

(að) barnið mitt noti alltaf hjálm
– that my child always uses a helmet (my child = subject)

This can be confusing because in a different sentence you could also have:

Ég sé barnið mitt. – I see my child.

Here barnið mitt is accusative (object), but the form looks identical to the nominative. The difference is purely syntactic (subject vs. object), not visible in the ending.

Can the overall word order be changed much, or is Ég vil að barnið mitt noti alltaf hjálm svo það lendi ekki í slysi basically fixed?

The given sentence is in very neutral, standard word order, and most of it is not easily changed without sounding marked or strange.

What is fairly flexible (but often adds emphasis):

Position of adverbs like alltaf and sometimes ekki:
- Ég vil að barnið mitt noti alltaf hjálm… (neutral)
- Ég vil að barnið mitt alltaf noti hjálm… (emphasis on always)
- …svo það lendi ekki í slysi. (neutral)

What is not really flexible:

Ég vil að… – you need að before the finite verb noti.
The subject–verb order in the subordinate clauses:
- barnið mitt noti, not noti barnið mitt (in this kind of that-clause).
- það lendi ekki, not lendi það ekki in neutral style.

So small shifts (especially with adverbs) are possible, but the basic skeleton:

Ég vil [að + subject + verb + adverb + object] svo [subject + verb + ekki + prepositional phrase]

is what you should keep.