Chemish - the scientific language of chemistry - is crucial for learning chemistry. To help students acquire the competencies to understand and use Chemish, chemistry teachers need to have a sound knowledge of teaching and learning Chemish: Pedagogical Scientific Language Knowledge (PSLK). But still, despite the importance of this knowledge, the question remains what exactly it is. Based on a model for science teachers' PSLK developed through a systematic review, this study seeks to validate the developed model by interviewing experienced chemistry teachers, filling the model with more detail, and examining further and systematising chemistry teachers' PSLK. Therefore, semi-structured interviews with 19 German secondary chemistry teachers are conducted. The interviews are analyzed both deductively using the results of the systematic review and inductively following the approach of Grounded Theory. Finally, the elements of PSLK resulting from the systematic review, as they are knowledge of (i) scientific language role models, (ii) the development of the concept before the development of the scientific language, (iii) making scientific terms and language explicit, (iv) providing a discursive classroom, (v) providing multiple resources and representations, (vi) providing scaffolds for scientific language development, (vii) communicating expectations clearly, and (viii) specific methods and tools for teaching and learning the scientific language, could be validated and described in more detail, and even new elements, as they are the knowledge of (ix) the motivation when learning scientific language as well as (x) the knowledge of lesson preparation and follow-up, could be identified and described through the interviews. Furthermore, elements influencing the development of and PSLK itself are characterized. Implications to foster Pedagogical Scientific Language Knowledge during teacher preparation will be given.