"The Language Movement catalysed the assertion of Bengali national identity in Pakistan..."

"... and became a forerunner to Bengali nationalist movements, including the 6-point movement and subsequently the Bangladesh Liberation War in 1971. In Bangladesh, 21 February is observed as Language Movement Day, a national holiday."

Bangladesh is today's "History of" country.

Here is the monument to the Language Movement martyrs:

 

What was so important about language?

When the state of Pakistan was formed in 1947, its two regions, East Pakistan (also called East Bengal) and West Pakistan, were split along cultural, geographical, and linguistic lines. In 1948, the Government of Pakistan ordained Urdu as the sole national language, sparking extensive protests among the Bengali-speaking majority of East Pakistan. 

Would East and West Pakistan be one country today if the government hadn't been so hardcore about Urdu?

Great differences began developing between the two wings of Pakistan. While the west had a minority share of Pakistan's total population, it had the largest share of revenue allocation, industrial development, agricultural reforms and civil development projects. Pakistan's military and civil services were dominated by the fair-skinned, Persian-cultured Punjabis and Afghans. Only one regiment in the Pakistani Army was Bengali. And many Bengali Pakistanis could not share the natural enthusiasm for the Kashmir issue, which they felt was leaving East Pakistan more vulnerable and threatened as a result.