While there has been insightful research on the commonly used expression "I think" (IT), this study introduces a non-conventional and innovative conception of elasticity (Zhang 2011), bringing together several properties of IT. Drawn on large-scale naturally occurring classroom data with a rare combination of linguistically and culturally contrasting groups of L1 (American English) and L2 (Chinese- and Persian-speaking learners of English), this study shows that the elasticity of IT is manifested through three stretchable, non-discrete, and fluid continua: frequency, position, and cluster. The patterns show that L1 and L2 speakers stretch IT to variable degrees and stop at variable points along the three continua. A striking finding is that L1 speakers are speaker-oriented and assertive, the Persians are listener-centred and less authoritative, and the Chinese tend to take the middle-ground position. The findings imply that some discrepancies between L1 and L2 should not necessarily be labelled as overuse or underuse: they may simply be different focuses and preferences. The awareness of linguistic elasticity is crucial to communicative success.