SCCM +W10 yes, but not language/speech packs. 

When I deployed Māori language pack for office, we had problems with the office updates in sccm - issue was it did not download the Māori parts, just English and Māori was not in the list to download. To fix it, we had to do the wmi bit in this https://docs.microsoft.com/en-us/sccm/sum/deploy-use/manage-office-365-proplus-updates#add-languages-for-office-365-update-downloads  and add the code for Māori - full list of codes here

What are you trying to achieve in particular out of curiosity? 

Depending on what language pack for what application you are wanting will differ between methods (ie DISM for base OS files, Powershell for enabling installed languages, msi installs for Office 2016 on prems, or via config.xml file for office 365. Unattaned.xml files for OS configuration etc.

Possibiliies are quite wide.

During the install we set the system locale to en-NZ, date formats etc to what we need, using the Win 10 Ent VSLC disc.  This works well, no real issues.

We have a few users with HP Elite x2 machines, one was trying to use the OneNote function of converting handwritten notes to text, but couldn't as they needed the Speech etc FOD elements installed.  I tried manually installing them from the en-US language pack, but this didn't appear to work.  Just wondering if anyone has any suggestions on which language pack you need/should be putting on, and how they are deploying them.

Thanks