Learn Hardcore Swahili: Mhariri alimshauri mwandishi wa habari aamue kama ataandika makala ndefu au fupi. - The editor advised the journalist to decide whether he will write a long article or a short one.

So alimshauri literally means “he/she advised him/her.”
In the sentence, the subject is mhariri (the editor), and the object is mwandishi wa habari (the journalist).

Why is there an -m- in alimshauri, and who does it refer to?

The -m- is an object marker. It refers to a third person singular, typically a person (him/her).

In this sentence:

subject: mhariri (the editor)
verb: alimshauri
object marker -m-: refers back to the journalist
full object noun: mwandishi wa habari

So we get: “The editor advised him, the journalist…”

In many contexts, you could also hear alishauri mwandishi wa habari (without -m-) and it would still be correct, but -m- makes the object more definite and personal (“that specific person”).

What is the difference between mhariri and mwandishi wa habari?

They are two different jobs:

mhariri = editor (the person who edits, supervises, or approves texts)
mwandishi wa habari = journalist / reporter (literally “writer of news”)

So the sentence talks about an editor advising a journalist, not about the same person.

Why is it mwandishi wa habari, not mwandishi ya habari?

The word wa is a genitive connector (“of”) that must agree with the noun class of the first noun.

mwandishi is in the M-/WA- (class 1/2) for people.
The genitive form for this class is wa.

So:

mwandishi wa habari = writer of news (journalist)
If the head noun were in a different class, the connector would change, e.g.:
- gari la habari (N.6) – “news car” (for a news vehicle)
- kitabu cha habari (N.7) – “book of news”

Ya is used with other classes (e.g. class 6/plural of non-people), so it would be wrong here.

Why is aamue spelled with two as?

The verb is kuamua = “to decide”.

To make the subjunctive for “he/she decide,” you add the subject prefix a- to the subjunctive stem amue:

a- (he/she) + amue (subjunctive of amua) → aamue

Swahili writes both a vowels, so you see aa in the spelling.
Pronunciation is usually a slightly lengthened [a].

Why is the subjunctive aamue used here instead of anaamua or ataamua?

Swahili uses the subjunctive to express things like:

commands
suggestions
wishes
what someone wants/asks/advises another person to do

After verbs such as kumshauri (to advise him/her), kutaka (to want), kuomba (to request), you commonly use the subjunctive:

Mhariri alimshauri mwandishi wa habari aamue…
= “The editor advised the journalist to decide / that he should decide…”

If you used normal tenses:

… anaamua = “he is deciding / he decides” (statement of fact)
… ataamua = “he will decide” (future fact)

Those don’t express the idea of advice or “should decide” as clearly as the subjunctive aamue does.

What does kama mean here – if or whether, and can it mean both?

Kama can mean “if” or “whether”, depending on context.

In this sentence the English translation is more naturally:

“… decide whether he will write a long or a short article.”

So here kama = whether.

In other sentences, kama often means if:

Kama atanipigia simu, nitaenda.
“If he calls me, I will go.”

So yes, kama can mean either if or whether, and the context tells you which is better in English.

Why is ataandika (future tense) used after kama instead of something like aandike?

Ataandika is the simple future form:

a- = he/she
-ta- = future
-andika = write
→ ataandika = “he/she will write”

After kama in a sentence like this, Swahili normally just uses the regular tense that fits the time:

aamue kama ataandika makala ndefu au fupi
= “decide whether he will write a long or a short article”

If you said aamue kama aandike…, you would also be grammatical, but the nuance shifts toward “decide whether he should write…”, sounding more hypothetical or prescriptive.
Ataandika here fits the idea of a simple future plan.

What kind of noun is makala, and how do you make its plural?

Makala usually belongs to the N-class (class 9/10), where the singular and plural often look the same.

makala (sg.) = an article, feature, essay
makala (pl.) = articles/features/essays

The number is usually shown by context or by agreement with verbs/adjectives:

Makala ndefu iliandikwa. – A long article was written.
Makala ndefu ziliandikwa. – Long articles were written. (zili- shows plural.)

In your sentence, makala is singular: “a long or short article.”

Why do the adjectives ndefu and fupi have no prefix, and how do they agree with makala?

Adjectives in Swahili agree with the noun class of the noun they modify.

makala is in the N-class (class 9/10).
Many adjectives in this class either take no extra prefix or a nasal (n-) prefix.

So you get:

makala ndefu = long article
makala fupi = short article

Both ndefu and fupi are forms that are used with N-class nouns.
You don’t need to repeat the noun:

makala ndefu au fupi literally = “an article long or short,” i.e. “a long or short article.”

This is very normal word order: noun + adjective.

Could the sentence be reordered, for example by moving aamue earlier, without changing the meaning?

Swahili word order is fairly flexible, but not completely free.
The typical pattern is:

Subject – Verb – Object – (Complement / Subordinate clause)

In your sentence:

Subject: mhariri
Verb: alimshauri
Object: mwandishi wa habari
Subordinate clause: aamue kama ataandika makala ndefu au fupi

You cannot naturally move aamue in front of the object like:

✗ Mhariri alimshauri aamue mwandishi wa habari…

That sounds wrong or confusing, as if mwandishi wa habari were somehow the object of aamue.

You can reorder bigger chunks with passive or topicalization, e.g.:

Mwandishi wa habari alishauriwa na mhariri aamue kama…
“The journalist was advised by the editor to decide whether…”

But inside the verb + clause complex, the order you have is the normal one.

Is a word like kwamba needed before aamue, as in alimshauri … kwamba aamue …?

No, it’s not required.

Swahili often uses the subjunctive alone to mean “that he should …” after verbs like kumshauri (to advise), kuambia (to tell), kutaka (to want), kuomba (to request):

Alimshauri aamue…
= “He advised (him) to decide / that he should decide…”

You can insert kwamba:

Mhariri alimshauri mwandishi wa habari kwamba aamue kama…

This is still correct and a bit more explicit, but many speakers will simply drop kwamba in everyday speech.

How do we know who is going to decide and who will write the article?

Both aamue and ataandika have the subject prefix a-, which just means “he/she.”
Formally, that could refer to:

the editor (mhariri), or
the journalist (mwandishi wa habari)

In practice, Swahili usually takes the subject of the subordinate clauses to be the most recently mentioned suitable person, so it naturally refers to mwandishi wa habari.

So the default reading is:

The editor (mhariri) advised
the journalist (mwandishi wa habari)
to decide whether he (the journalist) will write a long or short article.

If you needed to be extra clear, you could repeat the noun or add a pronoun:

Mhariri alimshauri mwandishi wa habari kwamba yeye mwandishi aamue…
Mhariri alimshauri aamue yeye mwenyewe kama ataandika…

But normally the original sentence is understood as referring to the journalist.