How do I say, "I have several co-workers who speak Filipino?"

Question

Answer

I'll make an attempt (probably terribly wrong !)..pasensya na  : meron akong ilan-ilang katrabaho na nagsasalita ng Filipino (Tagalog).

Answer

You can answer it different ways, such as: 
"May "ilang" ka-trabaho akong nagsasalita ng Tagalog" 
or 
"May 'mga' ka-trabaho ako na (akong) nag-sasalita ng Filipino (Tagalog)".

You can use "mangilan-ngilan" but it would mean "little or few".
Benoit's answer is also right, however, "ilan-ilang" is not commonly used nowadays.

Answer

May mga kasamahan akong pinoy 
May mga ka-trabaho akong pinoy 
/
May mga ilan-ilan akong kasamahan na nagsasalita ng Tagalog
May mga ilan-ilan akong ka-trabaho na nagsasalita ng Tagalog

Kasamahan is colleague/group
Ka-trabaho is co-workers

Pinoy is a word which "us" Filipinos call ourselves.
When meeting another Filipino that we aren't sure if they are, we ask them 
""Pinoy ka?" in English "Are you a Pinoy?"  Filipino is our identity, Philippines is our country, Pinoy is what we call ourselves.

Answer

"May mga ka trabaho ako na nagsasalita ng Tagalog". Filipino refers to the people like Americans and the language is called Tagalog.