Chalk Index

Berlitz, EF Corporate, goFLUENT, Voxy — and Preply Business and Babbel for Business — all surface languages, formats, integrations, case studies, and named clients on their public pages. None publish per-seat rates. The transparency gap is the mechanism.

Stated salary makes JET look like the highest payer and AEON look mid-pack. The all-in package — base + housing + airfare + severance — promotes hagwons and EPIK and drops AEON to last.

Preply has a Business English specialty tag (16,481 tutors, 38.7%). italki has a filter chip 94% of teachers apply. Wyzant has no Business English category at all — its ESL/ESOL subject is the closest equivalent. Three taxonomies, one vertical.

Two tests, two buyer populations, three platforms. The rate gap is small everywhere except Wyzant — and the specialist premium only exists in one of the three markets.

And whether the three biggest online marketplaces are actually where the TOEFL prep market lives.