Ego commemorō! is a Latin equivalent of the English phrase "I remember!" The subject pronoun need not be used except for emphasis since clarity is served by context and verb endings. The pronunciation will be "EY-go kom-MEY-mo-RO" in Latin.
"He" is English is the personal pronoun is in Latin.
The verb est in Latin is "is" in English.
Testamentum in Latin is "testament" or "will" in English.
"Mind" in English is mens in Latin.
"Short" in English is brevis in Latin.
Quī in Latin means "what" or "which" or "who" in English.
M in Latin is "1,000" in English.
Infernus in Latin is "hellish" in English.
"Life" in English is vita in Latin.
"Humility" in English is humilitas in Latin.
"Family" in English is familia in Latin.
"Are you with me?" in English is Estis cum me? or Estis mecum? in Latin.