The basic foundation of a rap flow revolves around the last word in each bar, or rhyming line, of a rap lyric. Basic flows may be performed with lyrics that rhyme a single syllable. An example of this is two lines ending with the "urt" sound, such as in the words "dessert" and "hurt." Such basic flows are common in amateur raps and are better suited to the learning and practice of rapping than to finished records. Basic monosyllabic flows are also commonplace in improvised freestyles, as more complicated rhyme patterns are difficult to produce on-the-spot.
Multisyllabic rhymes are more complicated and allow for a more diverse and intriguing flow. Rhyming multiple syllables in a lyric — for example, rhyming the words "lyrical devastation" with "hysterical presentation" — can create an interesting flow with opportunity for a more unique delivery. Rhyming multiple syllables allows rappers to present wittier rhymes, because they can shift emphasis to different syllables as needed for a larger variety of rhyming words.
Depending on the subject matter of the song, rappers may choose to use a more upbeat tone or express different emotions with their voices while rapping. The "feel" or vibe of a song depends, at least in part, on its flow. To successfully convey specific emotions in a rap, a rapper must pay attention to his tone. Another factor in analyzing rap flows is the enunciation of lyrics. Choppy, short rhyme patterns that are strongly enunciated are often heard in "underground" or competition raps. Mainstream rap music often has less emphasis on the enunciation of lyrics than battle-style rap songs, but may have a more catchy sound.
The speed of a rap flow is its most obvious trait. Fast raps can be impressive and contain more lyrical content, whereas slow raps are easier for fans to memorize. An example of a rapper known for his fast-paced flow is Bizzy Bone from the rap group Bone Thugs-n-Harmony. On the other side of the scale, Houston rapper Lil' Flip is known for his slow and relaxed flow. Slow flows may have a wider cross-genre appeal, and are generally easier to perform. Rapping fast sometimes presents issues with breathing in between lines.