Particles are small words attached to nouns and phrases that define their grammatical role in a sentence. Several core particles deserve attention first. The particle は (written "ha" but pronounced "wa") marks the topic of a sentence, telling the listener what the conversation is about, as in わたしはがくせいです (watashi wa gakusei desu, "As for me, I am a student"). The particle が, by contrast, marks the subject and is used when introducing new or emphasized information, such as in だれがきましたか (dare ga kimashita ka, "Who came?"). The particle を (pronounced "o") marks the direct object of an action verb, while に indicates location of existence, time, or destination, and で marks the location where an action takes place or the means by which it is performed.
Other particles show relationships between nouns or add sentence-level meaning. の connects nouns in a way similar to "'s" or "of" in English, as in わたしのほん (watashi no hon, "my book"). へ (written "he" but pronounced "e") indicates direction of movement, similar to に but emphasizing the path rather than the endpoint. と means "and" when listing nouns or "with" when expressing companionship. The question marker か is placed at the end of a sentence to turn it into a question, and も means "also" or "too," replacing は, が, or を to indicate inclusion.
Several particles handle temporal and spatial ranges or add emphasis. から means "from" and marks a starting point in time or place, while its pair まで means "until" or "up to" and marks an endpoint, often used together to express a span such as "from 9 until 5." The sentence-ending particle よ adds emphasis or conveys new information to the listener, as in おいしいですよ (oishii desu yo, "It's delicious, you know!"). Together, these particles form the structural skeleton of Japanese sentences, and learning them early dramatically improves comprehension and fluency.