 One of its unique features is a "hook/tilde dictionary" (), which provides spelling suggestions for distinguishing words with or tones.This feature is helpful for speakers of dialects in which these two tones have merged.The "VPS" character encoding for writing Vietnamese replaces several control characters, including several C0 control characters, with letters while including the ASCII graphical characters unmodified, a similar approach to VSCII-1 (TCVN1) and VISCII.