How to show language specific search result in Solr search
use entity translation ...Regarding Entity Translation introductions:


Enable language fallback 
Display shared labels 
Select which entities can be translated: Node;Commerce product
Details for Commerce product: Selected Author's language and no
checkboxes at all


Languages selection/detection (admin/config/regional/language/configure):


Selected/added all necessary languages, still leaving English as
default, manually added en prefix for English default, to make clear
separation, as I am using prefix for language separation
User interface text language detection: URL; Default
Content language detection: Interface (moved to top manually); URL;
Default


Commerce product type settings (admin/commerce/products/types/product/edit):


Enabled via Entity Translation

admin/commerce/products/types/product/fields
Replaced regular Drupal Title field with Title module, and in this
field settings checked, that this is the only field in Product type
I'm going to allow translation.

Product display node content type settings from admin/structure/types/manage/{your-display-type}
Published options > Multilingual support - selected: Enabled, with
translation (NOT Enabled, with field translation, as I'm going to use
i18n for language and node separation).
My title field in this display node, which is overridden by Title
module is left for field translation, as these are per field
settings, not per content type.
There are no any other fields let for entity translation in product
display node, even product reference field (used with inline entity
form).


Basically that's all. Taxonomy term translation is handled by i18n modules and Taxonomy vocabulary has Translate... (NOT Localize...) settings - different name for each language tied into translation sets.