であろう

Auxiliary (used in writing and formal speech only) (Intermediate ㊥ 29)

An auxiliary which indicates the writer's conjecture which is not based on any particular information or evidence.

Equivalent: Probably

日本経済は今後も成長を続けるであろう。: The Japanese economy will probably still keep growing (literally: from now on, too).
このようなブームはもう二度と起こらないであろう。: Such a boom will probably not happen again.
この次に起こる地震は非常に大きいであろうと予想される。: It is expected that the next earthquake will (probably) be very strong.
その交渉は極めて困難であろう。: That negotiation will probably be very difficult.
この辺りは昔、湖だったであろうと思われる。: I think that this area was probably a lake a long time ago.

Formation

Sinformal	であろう
	{話す/話した} であろう	Will probably talk/probably talked
	{高い/高かった} であろう	Is/was probably expensive
	{静か/静かだった} であろう	Is/was probably quiet
	{先生/先生だった } であろう	Is/was probably a teacher
Exception	{Adjective な stem/Noun}であろう

Notes