The first difficulty

[keannu]

Self practice
[FONT=&#48148]As a failure analysis engineer, my additional roles were to manage technicians and to make them become engineers. The first difficulty was to make them study English. Most of them were high school graduates, so they hadn’t studied English hard before. But most engineer papers are written in English, so they found it hard to under stand them.[/FONT]

Does the underlined sound natural?

 

[Tarheel]

The underlined part isn't terrible, but the rest is pretty bad. Did you really mean to say you forced them to study English? (That's the sense of "make" the way you used it both times.)

 

[SoothingDave]

"First challenge" sounds better to me.

 

[Tarheel]

Perhaps:

But most engineering papers are written in English, so they couldn't understand them.

 

[Tarheel]

Perhaps:

As a failure analysis engineer, in addition to my other jobs I manage technicians and help them become engineers.