Very, very difficult.
“My son got his degree in Mandarin from UC Davis.”
A longtime friend learned Mandarin at the Naval Language School in Monterey, and he spoke and read Spanish before his Monterey/Mandarin classes.
This was during the last year of our war II with Japan/Germany.
He and his classmates never got answers to why Mandarin instead of Japanese or German.
They soon found out why at the end of WWII
I took 6 semesters of Mandarin Chinese from a community collage and private lessons. I no longer had to travel to China so I gave up the classes about 15 years ago.
Then I married a woman from Guangzhou. She spoke Cantonese in the home with our son, a local Guanxi dialect with her family and Mandarin with the neighbors. I found Cantonese has 9 tones. I thought Mandarin was hard to hear the tones with my old ears... Cantonese was worse. I didn’t even try.
When my wife move to the US, I asked if she would yell at me in Chinese if she got angry. She told me that she would yell at me in English because she wanted me to understand every word she said.
That’s impressive. It always seemed like a difficult language.
I went to China (Shanghai and Zhangjiagang) on business in early ‘01 and learned the standard “Hello/Goodbye/Thank you…”
The only phrase I remember from then is how to say “I’d like another beer.” (phonetically “tsai lai eeping pidjio.”)