Learn Spanish (Latin America): Su hermana menor tiene cinco años.

Su hermana menor tiene cinco años.

His younger sister is five years old.

Breakdown of Su hermana menor tiene cinco años.

his/her/its/their/your (formal)

Questions & Answers about Su hermana menor tiene cinco años.

Why does the sentence use menor instead of más joven for "younger"?

While you can say más joven (literally "more young"), it is much more natural and common to use the irregular comparative menor when talking about ages, especially with family members. It directly translates to "younger".

Would menor change to a masculine form if we were talking about a younger brother?

No, it stays exactly the same! Because menor ends in a consonant, it does not change based on gender. You would say el hermano menor for a brother and la hermana menor for a sister. It only changes when it becomes plural (menores).

Why does the Spanish sentence say she has (tiene) five years instead of is five years old?

In Spanish, age is expressed as something you possess rather than a state of being. You always use the verb tener (to have) for age. So, you literally say someone "has" five years (tiene cinco años) rather than "is" five years old.

How do we know su means "his" in this sentence? Could it also mean "her" or "your"?

Yes, su is a possessive adjective that can mean his, her, your (formal), or their! Without more context, this sentence could absolutely mean "Her younger sister" or "Your younger sister". We only know it translates to "His" here because of the wider context of the conversation it came from.