In this case the native tongue of the Scouts is immaterial. They have no need to communicate with your team. When selecting your team captain you should consider the Influence and Teamwork attributes. Although not too critical the age should be 24 or above. In other words not what the game considers to be a 'young player'.
Experience does help.
You always have the option of allowing the AI to select your captain. It can help to have an agile goalkeeper with good Anticipation when you are playing certain tactics so although not listed the Agility and Anticipation attribute can be important for them. Passing Desired Values. The level at which a player can perform is set by the numerical value within each attribute. This also determines the level at which a player can initially play.