Learn Hardcore French: Les statistiques montrent qu’une petite somme d’argent suffit souvent pour changer l’humeur de quelqu’un. - The statistics show that a small amount of money often suffices to change someone’s mood.

Les statistiques is plural (like the statistics in English), so the verb must be plural: montrent.
The singular would be la statistique → la statistique montre.

So:

Les statistiques montrent… = The statistics show…
La statistique montre… = The statistic shows…

Why do we use les in les statistiques? Could we just say statistiques montrent?

In French, common countable nouns almost always need an article; you can’t usually leave it out as in English.

Les statistiques with les (definite article) is the usual way to talk in general about statistics as a body of data or knowledge.
Saying statistiques montrent without an article is ungrammatical in standard French.

Alternatives you might see:

Les statistiques montrent que… (most natural)
Selon les statistiques, … (according to the statistics, …)

What is qu’ in montrent qu’une petite somme…, and why is there an apostrophe?

Qu’ is just que (meaning that) with elision.

Que becomes qu’ in front of a word that begins with a vowel sound or mute h, to make pronunciation smoother:
- que une → qu’une
- que il → qu’il
- que elle → qu’elle

So qu’une literally = que une (that a), but written and pronounced as one unit: qu’une.

Why is it une petite somme d’argent and not un petit somme d’argent?

Because somme is a feminine noun in French.

une somme = a sum / an amount
Feminine adjectives and determiners must agree:
- une petite somme (feminine: une, petite)
- not un petit somme (masculine, incorrect)

Compare:

un petit problème (masculine)
une petite somme (feminine)

You just have to memorize the gender of somme as feminine.

What is the nuance of une petite somme d’argent compared to un peu d’argent?

Both refer to a small quantity of money, but the nuance is different.

une petite somme d’argent
- Treats money as a specific amount (a sum) that could be counted or named.
- Sounds a bit more formal or objective, often used in writing or when talking about amounts in a more measured way.
- Can suggest: not a lot, but still a real, concrete sum.
un peu d’argent
- Literally: a little money / some money.
- More vague and informal; focuses on small quantity rather than the idea of a defined sum.

In this sentence, une petite somme d’argent matches the idea that even a relatively small amount (e.g., a bonus, a small gift, a tip) can change someone’s mood.

Why is it d’argent and not de l’argent after une petite somme?

After a noun of quantity like une somme, beaucoup, peu, etc., French uses de (or d’ before a vowel sound), not de + article.

Pattern:
- une somme d’argent
- beaucoup d’argent
- un kilo de pommes
- un verre de vin

So:

une petite somme d’argent (correct)
une petite somme de l’argent (incorrect in this meaning)

We use d’ because argent begins with a vowel sound: de + argent → d’argent.

Why is the adverb souvent placed after the verb in suffit souvent? Could it go somewhere else?

In French, many common adverbs (like souvent, toujours, rarement) typically go after the conjugated verb in simple tenses:

suffit souvent = often suffices / is often enough
vient souvent = often comes

Other possible positions are:

At the beginning of the clause (more emphasis on the frequency):
- Souvent, une petite somme d’argent suffit pour changer…
  → Often, a small amount of money is enough to change…
Very occasionally after the entire verb phrase, but that can sound less natural or slightly more literary in a sentence like this.
- Une petite somme d’argent suffit pour changer l’humeur de quelqu’un, souvent. (adds often as an afterthought)

In your sentence, suffit souvent is the most neutral and natural placement.

How does suffit pour changer work? Why suffire pour + infinitive here?

The structure is:

suffire pour + infinitive = to be enough to + verb

So:

une petite somme d’argent suffit pour changer l’humeur…
→ a small amount of money is enough to change the mood…

Common patterns with suffire:

suffire pour faire quelque chose
- Ça suffit pour vivre. = That’s enough to live on.
suffire à quelqu’un / à quelque chose
- Ça lui suffit. = That’s enough for him / her.
- Ce salaire suffit à notre famille. = This salary is enough for our family.

Here we want “enough to change”, so pour + infinitive is the right pattern.

Why is it just pour changer and not pour de changer or à changer?

After pour (meaning for / in order to), French uses a bare infinitive — no de, no à:

pour changer = (in order) to change
pour comprendre = to understand
pour réussir = to succeed

So the correct patterns are:

suffit pour changer (correct)
suffit pour de changer (incorrect)
suffit à changer is not a standard way to express this idea; we normally say suffire pour + infinitive.

Why is it l’humeur and not la humeur?

Again, this is elision:

The noun humeur is feminine:
- la humeur in theory
But la becomes l’ in front of a vowel sound or mute h:
- la humeur → l’humeur
- la amie → l’amie
- la eau → l’eau

So:

l’humeur = the mood
Written with an apostrophe to show the dropped vowel.

Why do we say l’humeur de quelqu’un for “someone’s mood” instead of using something like quelqu’un’s or à quelqu’un?

French doesn’t have the apostrophe-s possessive like English. Instead, it usually uses de + person:

l’humeur de quelqu’un = someone’s mood
le livre de Marie = Marie’s book
la maison de mes parents = my parents’ house

Using à can express possession in some fixed patterns, especially with body parts or personal belongings, but here de is the normal choice:

changer l’humeur de quelqu’un (natural)
changer l’humeur à quelqu’un sounds odd; you might hear ça lui a changé l’humeur, but that’s a different structure (with an indirect object pronoun lui).

So de is the standard “of/’s” marker in this context.

What exactly is quelqu’un? Why the apostrophe, and can I write quelque un?

Quelqu’un is an indefinite pronoun meaning someone / somebody.

It is written as one word with an apostrophe: quelqu’un
You should not normally write quelque un as two words (except in very rare, special emphatic or poetic uses).

The apostrophe is historical; synchronically you can just remember:

quelqu’un = someone
quelque chose = something
quelques (plural adj.) = some, a few (e.g. quelques personnes = a few people)

So l’humeur de quelqu’un literally = the mood of someone → someone’s mood.