What's the difference between a lyricist, a composer, an arranger and an arranger?

In layman's terms, lyric writing is to write the lyrics for a song. Songwriting is writing the melody for a song (the melody that the singer sings), and arranging the melody for a song with background music (such as a combination of drums, guitars, pianos, and other instruments).

Songwriting: The so-called songwriting refers to the writing of words to express feelings for a song. From the Book of Songs to the Song of Songs, from the ancient tribal songs to today's local operas, all the lyrics are written because of the "song". Because human beings are born with emotions, when they need to vent or express them, they need to "sing", and in the process of "singing", they need appropriate words to fill them. So, the concept of lyrics was born.

Composition: The writing of the melody of a song. Music terminology, composition (Composition, in non-musical content to describe the composition will use Musical composition). Is the act of creating music, or the process of creating music. It may also denote the creator of a musical composition. The method of expressing the creator's musical ideas by using the technical theoretical systems of harmony, polyphony, orchestration, and compositional structure. The compositional styles and technical methods vary from country to country and from historical period to historical period, and are broadly categorized into various styles such as Baroque, Classical, Romantic, and Modern.

Arranging: The term "arranging" means "arranging" in Japanese, and is translated as "へんきょく" in Chinese. In Chinese, it is translated as an adaptation (of a musical work). It is a compositional work of rearranging an existing completed musical work partially based on the material.

Arranging is the process of arranging the chords, matching the instruments, designing the pattern, writing the harmonies, and mixing the accompaniment of the song, which is a complex production process and not as simple as composing.