Creating language files for Symbio is pretty easy. Just make new file with the name of your language (preferably in lowercase) followed by .txt, and put the translation of each of the expressions below on a separate line. Be sure to start at line 1 and follow the exact order. To use it, place the file in the languages subdirectory, log into your control panel and change the language preference.
If you've created a language file, please send it to me; to express my gratitude, I'll mention you on the site.

Anatomy of a language file

Line Expression Notes
1 You need to fill out the form properly to post a comment. Go back <a href="javascript:void(history.go(-1));">here</a>. The user didn't fill out the commenting form properly; leave the link HTML intact.
2 Sorry, couldn't write to the comment file. Error message when a comment file is read-only.
3 What did others have to say? Title text for the comment list.
4 What do you have to say? Title text for the commenting form.
5 Sorry, this article has been locked. You can no longer post comments to it. Administrator has locked the article.
6 Please enter the text you would like to Generic start of the layout prompt text; the expressions below will be appended to it appropriately; there is no space before the appended text, so don't forget to add one if needed.
7 underline.  
8 strikethrough.  
9 put in italic.  
10 put in bold.  
11 Please enter the URL you would like to link to. Text for the URL prompt.
12 Please enter the text you would like to link. Text for the link text prompt.
13 Smileys are now ON. Please reload the comment list for changes to take effect.<br>Click <a href="<!toggle>">here</a> to turn them off again. Text for the popup when smileys are turned on; add a link to <!toggle> which will allow the user to turn them off again.
14 Smileys are now OFF. Please reload the comment list for changes to take effect.<br>Click <a href="<!toggle>">here</a> to turn them on again. Text for the popup when smileys are turned off; add a link to <!toggle> which will allow the user to turn them on again.
15 Available smileys Title for the smiley list in the help popup.
16 turn ON Text for the link after line 15 to turn smileys on if they are off.
17 turn OFF Text for the link after line 15 to turn smileys off if they are on.
18 or Text between smiley codes in the help popup.
19 Layout tags Title for the layout tag list in the help popup.
20 will result in Text between the layout tag code and the rendered result.
21 cheesy poofs Example text for "bold" layout tag.
22 screw you guys Example text for "italic" layout tag.
23 beefcake Example text for "underline" layout tag.
24 authoritah Example text for "strikethrough" layout tag.
25 dude! Example text for "hyperlink" layout tag.
26 http://goatse.cx/ Example URL for "hyperlink" layout tag.
27 Some statistics Title for the statistics in the help popup.
28 updated hourly Appendix for the statistics title.
29 top <!num> commenters Title for the top commenter table; <!num> is replaced with the size of the table.
30 comments Title for the number of comments in the top commenter table.
31 the numbers Title for the counts and averages in the statistics.
32 articles with comments Field in the statistics.
33 comments Field in the statistics.
34 commenters Field in the statistics.
35 average comment length Field in the statistics.
36 chars Appended to character count in average comment length.
37 average comment per article Field in the statistics.
38 average comment per person Field in the statistics.
39 average comment per day Field in the statistics.
40 top comments per article Field in the statistics.
41 busiest day Field in the statistics.
42 with Field in the statistics
43 comments Appended to comment count for the busiest day.
44 No-one has commented on this article so far. No comments for the article yet.
  The lines below are new in version 1.2 language files. If your file hasn't been updated yet, please contact the author.
45 Name Where the commenter enters his name on the commenting form; also used in the post output.
46 E-mail Where the commenter enters his e-mail address on the commenting form; also used in the post output.
47 WWW Where the commenter enters his homepage URL on the commenting form; also used in the post output.
48 Comments Where the commenter enters his comments on the commenting form; also used in the post output.
49 Bold Label or tooltip text for the appropriate layout button.
50 Italic Label or tooltip text for the appropriate layout button.
51 Underline Label or tooltip text for the appropriate layout button.
52 Strikethrough Label or tooltip text for the appropriate layout button.
53 Hyperlink Label or tooltip text for the appropriate layout button.
54 Help Label or tooltip text for the button which opens the help popup.
55 Post Label or tooltip text for the submit button.
  The lines below are new in version 1.3 language files. If your file hasn't been updated yet, please contact the author.
56 Date Title of the date field in the post output.
57 Click here Text for e-mail and URL links in the post output.
58 Not available Used when e-mail or URL in the post output is blank.
  The lines below are new in version 1.5 language files. If your file hasn't been updated yet, please contact the author.
59 Care to cast your vote? Title text for the poll.
60 Votes Title text for number of votes in poll.
61 This poll is locked, so you cannot vote in it. Displayed instead of possible answers when poll is locked.
62 The site owner has decided to keep the results of this poll secret. Displayed instead of results when results are kept secret.
63 No-one has voted in this poll. Displayed instead of results when no-one has voted yet.
64 You have already voted in this poll. Go back <a href="<!url>">here</a>. Displayed when the user tries to vote a second time; <!url> is replaced with the URL the user should go back to.
65 This poll is locked, so you cannot vote in it. Go back <a href="<!url>">here</a>. Displayed when the user tries to vote in a locked poll; <!url> is replaced with the URL the user should go back to.
66 An error occurred while registering your vote. Go back <a href="<!url>">here</a>. Displayed when an unknown error occurs while registering the user's vote; <!url> is replaced with the URL the user should go back to.
67 The poll you attempted to vote in could not be found. Go back <a href="<!url>">here</a>. Displayed when the poll file does not exist, probably because it has been deleted in the period between opening the page and voting; <!url> is replaced with the URL the user should go back to.
68 polls Field in the statistics.
69 average answers per poll Field in the statistics.
70 average votes per poll Field in the statistics.
  The lines below are new in version 1.6 language files. If your file hasn't been updated yet, please contact the author.
71 The site owner has decided not to let anyone post comments from your IP address. Displayed instead of commenting form if the user's IP is banned.
  The lines below are new in version 1.7 language files. If your file hasn't been updated yet, please contact the author.
72 Poll results Link text to skip voting.
73 Your comment was successfully saved, but the site owner has enabled comment moderation. The comment will not be published until it has been approved. Post confirmation text when moderation is turned on.
74 Click <a href="<!url>">here</a> to go back to the comment list. Text that sends the user back to the comment list after posting when moderation is turned on; <!url> is replaced with the URL the user should go back to.
75 Comments Placed after the number of comments in each item of the RSS feed; plural. Mind the capital letter.
76 Comment Placed after the number of comments in each item of the RSS feed; singular. Mind the capital letter.