primary tone marked with double acute accent: 'bőőulo', bubble
secondary tone marked with single acute accent: 'ésti', but, however, yet, although
base tone unmarked: 'ṡa', just, but a little distance

"Tone is lexically significant in Modernized Lefso, often marked excessively by speakers. Tone is governed by three components: The director component of an Occupied Lefse, A Toner, and a Blank Lefse. 

A Toner is similar to a Hiragana “Ku,” which was misinterpreted and borrowed from a Japanese Novel. This resulted in a dialect taking a major swing and repurposing the “Ku” as a Toner symbol, with the period turning into the indicator—it on the lower line meant a falling tone, and it placed on the higher line meant a rising tone.

The Lefse is considered the most important symbol. Consisting of a “Stage” (often occupied by a character) and a “Director,” an arrow-shaped item placed either center-top, bottom-right, or center-right. There are two types of Lefse: Blank and Occupied. A Lefse is every space possible where letters may take these up. Every Odinya character used in a sentence is considered an Occupied Lefse, as the letter (better in this context, “Sound Component), takes up the space of a Lefse, and the Director is positioned at the bottom-right of the character (with exceptions being la, le, li, lo, lu, pa, pe, pi, po, and pu). A Blank Lefse is a modifier character. It’s rare and is used for specific cases, such as:

A complicated sound with fluctuating tone, A toner, and Lefse must be used in alternation when doing so.
Tone/Length marking at the end of a word.
When a complicated sound requires more than one elongation/glottal stop marker.
Altering the entire tone midway through a sentence, via duplicating the character.

A Lefse may only hold one director.

A Director shows what to do within a character. Pointing up or down indicates a rising or falling tone, while a left/right-oriented arrow indicates character elongation (left-facing), or shortening of aspiration or voice length. Sometimes marking a succeeding glottal stop. Tone markers alter everything after it (until the end of a word or another tone marker is used in said word).

The usage of Toners and Blank Lefses has varying influence on sounds depending on their placement and usage. A Blank Lefse, if used for tone, indicates that all components succeeding it must rise/fall in tone; exceptions being if it’s being alternated with a Toner for a complex tone, or if two Lefses are marked in the same direction downwards. A toner only affects its preceding character. When tone changes are marked, tone shifts 30 - 40% from its starting point. Aspiration is also affected by tone."

Cited from Lefso's Kawiki page