“soooo”
Soooo stretches the spelling of so to suggest a long, emphatic sound, much like drawing out a word when saying “I'm so hungry!” The same spelling appears in soooo bored in A1-27.
A1-03 / CEFR A1 / EPISODE 03
Ordering at the cafeteria
SceneA busy school cafeteria at lunchtime.

WORDS & CONTEXT
Soooo stretches the spelling of so to suggest a long, emphatic sound, much like drawing out a word when saying “I'm so hungry!” The same spelling appears in soooo bored in A1-27.
Something is no joke means that it is serious, or no laughing matter. Tina uses hunger as the subject to make an exaggerated appeal: “Don't underestimate being hungry!”
Shake is short for milkshake, a standard drink at a burger restaurant. A burger, fries, and a shake is a classic American combination.