A non‐invasive photoglottographic method has been developed for monitoring glottal aperture changes during speech for the purpose of phonetic and clinical studies. The system includes light‐source and sensor units both placed externally on the neck. An LED light source on the side of the neck illuminates the hypopharynx diffusely, and a photo‐sensor unit on the front neck below the cricoid cartilage detects light passed through the glottis. An ambient light rejection circuit was newly added to avoid the effect of room light. The photoglottography (ePGG) system is free from interference due to tongue retraction and thus operational both in high‐ and low‐vowel environments, while it is susceptible to articulatory movements of the jaw and larynx. We will present new ePGG/airflow data to explain why the apparent word‐initial strengthening of glottal opening occurs in our ePGG, as often observed in other previous PGG data. [Work supported by ESAPVI/ANR and Kakenhi 21300071.]