The spelling of the word "grieb" may seem unusual at first glance, but it can be explained with IPA phonetic notation. The first sound in "grieb" is a voiced velar fricative, represented by the symbol /ɡ/. The second sound is a voiced alveolar approximant, represented by the symbol /ɹ/. The third sound is a high front unrounded vowel, represented by the symbol /i/. The fourth sound is a voiced bilabial stop, represented by the symbol /b/. Therefore, the correct spelling of the word is "grieb."