Perhaps you should try some spelling variations:
"sung and soon letters" » "dung and soon letters", "cung and soon letters", "ung and soon letters", "sung and soan letters", "sung and son letters", "sung and yoon letters"
"sung and mon letters" » "dung and mon letters", "cung and mon letters", "ung and mon letters"
"song and soon letters" » "song and soan letters", "song and son letters", "song and yoon letters", "cong and soon letters", "dong and soon letters"

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (((("sung and soon letters") OR ("song and soon letters"))) or ("sung and mon letters"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("sung and soon letters") OR ("song and soon letters"))) OR ("sung and mon letters")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"sung and soon letters\") OR (\"song and soon letters\"))) or (\"sung and mon letters\"))".
• Removing quotes may allow a broader search: (((( sung and soon letters ) OR ( song and soon letters ))) or ( sung and mon letters )).
• Adding a wildcard symbol may retrieve word variants: (((("sung and soon letters") OR ("song and soon letters"))) or ("sung and mon letters"))*.