The Liberals have vowed to vote against Bill 14, and the Parti Québécois minority government needs CAQ's support in order to pass the legislation.
Legault said Friday that after four weeks of public hearings, his party's concerns about the bill have not waned.
"We said from the beginning that we have three conditions: military, municipalities and small companies," Legault said. "In listening to the different groups, there are two more items that have been added: the definition of cultural communities and the powers of the minister and the Office (québécois de la langue française.)
Language Minister Diane De Courcy says she, too, has listened to the many concerns raised by those who presented at legislative hearings into the bill.
'400 years of French heritage to protect'
However, she said with 400 years of French heritage to protect, her government must bolster safeguards, especially in Montreal.
That protection now hinges on whether De Courcy and Legault can reach a deal.
"I am hopeful it's possible to establish a dialogue," De Courcy said.
Legault said his conditions are not negotiable.
"We'll have to see if [the government is] open to making adjustments," he said. "If they don't make those adjustments, we will vote against Bill 14."
Next week the National Assembly votes on whether to send Bill 14 on for a detailed article-by-article review, which is where de Courcy says changes could be made.
The Liberals are still vowing to try and scrap the bill, leaving the balance of power in Legault's hands. It's still not clear whether the CAQ will vote to send the bill on to committee for further study, or whether it wants amendments made to the proposed legislation before any vote is held.
Legault said that decision will be left up to his caucus when it meets early next week.