彼はかんこく語を話すことができます。
- He can speak Korean.

彼はかんこく語を話すことができます。 meaning: He can speak Korean.

The sentence follows a typical Japanese sentence structure: Subject-Topic-Object-Verb. ⚫︎ The subject is 彼 (he). ⚫︎ The topic is established by the particle は (wa). ⚫︎ The object is かんこく語 (Korean). ⚫︎ The verb phrase is 話すことができます (can speak).

Particles are crucial in Japanese for marking the grammatical function of words in a sentence. ⚫︎ は (wa) is a topic marker. It indicates the topic of the sentence. In this case, it indicates that the topic is "he". ⚫︎ を (o) is a direct object marker. It marks the object of a transitive verb. Here, it marks かんこく語 (Korean) as the thing being spoken.

This part of the sentence expresses the ability to do something. ⚫︎ The verb 話す (hanasu - to speak) is conjugated to its potential form. ⚫︎ The basic potential form of a verb is formed by changing the final -u sound to -eru (for verbs ending in -u) or by adding -rareru (for irregular verbs) to the verb stem. However, for a small number of verbs, the potential form is formed with できる(dekiru - can do). ⚫︎ In this case, the verb 話す becomes 話せる, and the sentence ends with ことができます (koto ga dekimasu), which translates to "can." ⚫︎ This means the entire phrase 話すことができます translates to "can speak". ⚫︎ ことができます is the polite form of the potential form of the verb "to be able to do".

The verb 話す (hanasu - to speak) is in the present affirmative form, which is the dictionary form of the verb. ⚫︎ The dictionary form is used in this sentence to create the potential form. ⚫︎ To make the present affirmative polite form, you change the final -u sound to -imasu (e.g., 話します - hanashimasu - will speak/speak).

できます (dekimasu) is an auxiliary verb (or helping verb) expressing ability. ⚫︎ The verb できる (dekiru) means "can do" or "to be able to do." ⚫︎ It is used in conjunction with the potential form of another verb to indicate the ability to perform that action. ⚫︎ The polite form できます (dekimasu) is used to show respect to the listener.