Other difficulties include silent letters and consonant mutations. For silent letters, the word "chanthra" (written as จันทร์ in Thai) would be pronounced "chan" when spoken"." Notice that the suffix "-thra", written as ทร์ in Thai"," is missing in the phonetic spelling. That is because the Thai spelling is based on the Sanskrit spelling of the word, the language where the word comes from. Many loanwords in Thai are based on the spelling rules of the language they came from rather than their Thai pronunciation. Also, Thai words cannot end in any consonant that is not a nasal consonant, semivowel, or voiceless stop, the final consonants that are not either one of those mutate so that they can become pronounceable in Thai. For example, the word "wat" (meaning "temple") is spelled as "wad" (written as วัด in Thai), but since "-d", or ด, is a voiced alveolar stop, it must be pronounced as the voiceless alveolar stop "-t." Also, the name Bhumibol (written as ภูมิพล in Thai) is pronounced as "Phumiphon." The alveolar lateral approximant "-l" ,or ล, must be pronounced as the alveolar nasal "-n. The" English loanword "bus" (written as บัส in Thai) is pronounced "bat" in Thai. The voiceless alveolar fricative "-s" , or ส, must be pronounced as the voiceless alveolar stop "-t".