[quote=@Gunther]

A soldier in the infantry, would be in what type unit in the Finnish language? Would the terms Sissi and Jäger be used to identify a type of unit? 
[/quote]

Most Finnish infantry would be trained as Jägers. I'm not an expert on the military organisation during the wars. I'd recommend taking a look at the life of Lauri Törni, as he served in Finnish, German and American armies.