Learn Turkish: Çocuğun ruhsal sağlığı iyi. - The child's psychological health is good.

It is formed by adding the relational suffix -sal to the noun ruh (soul, spirit, or mind). The -sal / -sel suffix turns a noun into an adjective meaning "pertaining to" or "related to." Thus, ruhsal translates to "psychological," "mental," or "spiritual."

Why does the adjective ruhsal sit in the middle of çocuğun sağlığı (the child's health)?

In a Turkish genitive-possessive phrase, any adjective that modifies the possessed item must go directly before it. So the structure is çocuğun (the child's) + ruhsal (psychological) + sağlığı (health). If the adjective modified the child instead, it would go at the very beginning (e.g., mutlu çocuğun sağlığı meaning "the happy child's health").

Could I use akıl sağlığı instead of ruhsal sağlık to say "mental health" here?

They are related but carry different nuances. Akıl sağlığı (from akıl, meaning intellect or reason) is closer to cognitive function or "sanity." Ruhsal sağlık (from ruh, meaning soul or psyche) focuses more on emotional and psychological well-being, which is typically what we mean when discussing a child's mental health.

Why is there no "is" suffix like -dir at the end of iyi?