Mel, who took over at the English Premier League club last month, published his first book 'The Liar' in October 2011, the tale of a wealthy antiques collector who clashes with the Vatican while hunting for stolen manuscripts.
However, he arrived in England with little knowledge of the language and takes a one-hour lesson after completing a full day's work at the club's training ground.
"I have no time (to write), it's impossible," Mel was quoted as saying in an interview with Spanish sports daily Marca published on Friday.
"Any spare time I have to devote to learning English," added Mel, who will turn 51 at the end of February.
"My fatigue here is more mental than physical. I have to understand what they are saying to me, think in Spanish, translate into English and spit it out.
"One thing is the English you speak at the market, to buy things, and another football English. Learning how to say dead ball, close down space, defend as a unit... those are the difficult things.
"Little by little I am getting there. I have an English teacher and an interpreter for day-to-day problems, especially the news conferences."
Mel said he was pleased with the progress his players had made since he took over but added that it had also been a challenge to impose his style on the squad.
"I am trying to change the philosophy of a club which has been playing differently to my way for three years, not better or worse, different," he told the newspaper.
"A club that did not have my playing culture and that is not Arsenal or (Manchester) City with those kinds of players.
"For now I am happy with the way the players are taking the playing style on board.
"We have 13 finals ahead of us to confirm the best way forward and save ourselves (from relegation)."
West Brom are 17th in the standings, one place above the drop zone, and host bottom side Fulham on Saturday.