Short answers, pulled from the story.
The Commonwealth of the Philippines was an unincorporated territory and dependency of the United States that existed from 1935 to 1946. It was established by the Tydings-McDuffie Act as a ten-year transitional administration preparing the Philippines for full independence, which was granted on the 4th of July 1946.
Manuel L. Quezon was the first president of the Commonwealth of the Philippines, inaugurated on the 15th of November 1935. He won the first presidential election with nearly 68% of the vote against rivals including former president Emilio Aguinaldo and Obispo Maximo Gregorio Aglipay.
Japan launched a surprise attack on the Philippines on the 8th of December 1941, and occupied Manila on the 2nd of January 1942, forcing the Commonwealth government to flee. President Quezon and senior officials were evacuated by submarine from Corregidor on the 20th of February 1942, and established a government-in-exile at the Shoreham Hotel in Washington, D.C.
In 1937, the Commonwealth government selected Tagalog as the basis for a national language, made official by an executive order dated the 30th of December 1937, effective two years later. The National Language Institute, created by Commonwealth Act No. 184 in 1936, conducted the deliberations that led to this choice.
Estimates of Filipino war dead reached one million, and Manila suffered extensive damage when Japanese marines refused to vacate the city despite orders from the Japanese High Command. The prewar population had been estimated at 17 million in 1941.
Philippine independence came with significant economic conditions. Acceptance of the Bell Trade Act, also known as the Philippine Trade Act, was required as a precondition for receiving war rehabilitation grants from the United States. The act subjected the Philippine economy to continued American economic controls even after sovereignty was formally granted on the 4th of July 1946.